[NativeAOT-LLVM] Exclude ExceptionHandling.cs from the WASM build and pass -O1 to emcc

[SingleAccretion]

The non-WASM EH code roots almost 0.8% of HelloWorld code.

Diffs (WasmDebugging):

Summary of Code Size diffs:
(Lower is better)

Total bytes of base: 674872
Total bytes of diff: 669465
Total bytes of delta: -5407 (-0.80% % of base)
Average relative delta: 2.13%
    diff is an improvement
    average relative diff is a regression

Top method regressions (percentages):
         933 (134.05% of base) : 1049.dasm - S_P_CoreLib_System_Exception__ToString
         128 (54.94% of base) : 1031.dasm - S_P_CoreLib_System_Runtime_InteropServices_GCHandle___ctor
         140 (45.16% of base) : 1007.dasm - S_P_CoreLib_System_Runtime_RuntimeExports__RhUnboxAny
         119 (16.39% of base) : 1029.dasm - S_P_CoreLib_Internal_TypeSystem_LockFreeReaderHashtableOfPointers_2<S_P_CoreLib_Internal_Runtime_IDynamicCastableSupport_InstantiatingThunkKey__IntPtr>__Expand
         119 (15.78% of base) : 1028.dasm - S_P_CoreLib_Internal_TypeSystem_LockFreeReaderHashtableOfPointers_2<S_P_CoreLib_Internal_Runtime_IDynamicCastableSupport_InstantiatingThunkKey__IntPtr>__TryAddOrGetExisting
          15 ( 2.38% of base) : 1050.dasm - S_P_CoreLib_System_Runtime_TypeCast__AreTypesAssignableInternalUncached

Top method improvements (percentages):
        -185 (-81.14% of base) : 1030.dasm - S_P_CoreLib_System_Runtime_CachedInterfaceDispatch__RhpCidResolve
        -122 (-37.54% of base) : 1048.dasm - S_P_CoreLib_System_Runtime_TypeCast__AreTypesAssignable
        -198 (-21.45% of base) : 1038.dasm - S_P_CoreLib_System_Runtime_EH__DispatchException
        -119 (-17.73% of base) : 1047.dasm - S_P_CoreLib_Internal_Runtime_IDynamicCastableSupport__IDynamicCastableGetInterfaceImplementation
          -2 (-1.22% of base) : 1046.dasm - S_P_CoreLib_System_Runtime_DispatchResolve__FindImplSlotForCurrentType
          -5 (-0.95% of base) : 1008.dasm - S_P_CoreLib_Internal_Runtime_CompilerHelpers_StartupCodeHelpers__CreateTypeManagers

Top methods only present in base:
        -789 (-100.00% of base) : 1036.dasm - S_P_CoreLib_System_Runtime_EH__DispatchEx
        -715 (-100.00% of base) : 1012.dasm - StackFrameIterator::NextInternal()
        -657 (-100.00% of base) : 1042.dasm - S_P_CoreLib_System_Runtime_EH__FindFirstPassHandler
        -501 (-100.00% of base) : 1039.dasm - S_P_CoreLib_System_Runtime_EH__InvokeSecondPass_0
        -415 (-100.00% of base) : 1040.dasm - S_P_CoreLib_System_Runtime_EH__UnhandledExceptionFailFastViaClasslib
        -392 (-100.00% of base) : 1010.dasm - StackFrameIterator::InternalInitForStackTrace()
        -370 (-100.00% of base) : 1025.dasm - S_P_CoreLib_System_Runtime_EH__RhThrowHwEx
        -336 (-100.00% of base) : 1034.dasm - S_P_CoreLib_System_Runtime_EH__FailFastViaClasslib
        -333 (-100.00% of base) : 1044.dasm - S_P_CoreLib_System_Runtime_EH__AppendExceptionStackFrameViaClasslib
        -280 (-100.00% of base) : 1033.dasm - S_P_CoreLib_System_Runtime_EH__GetClasslibException
        -258 (-100.00% of base) : 1009.dasm - StackFrameIterator::CalculateCurrentMethodState()
        -211 (-100.00% of base) : 1015.dasm - RhpSfiNext
        -155 (-100.00% of base) : 1014.dasm - RhpSfiInit
        -134 (-100.00% of base) : 1024.dasm - S_P_CoreLib_System_Runtime_EH__RhThrowEx
        -115 (-100.00% of base) : 1021.dasm - S_P_CoreLib_System_Runtime_EH__RhpFailFastForPInvokeExceptionPreemp
        -110 (-100.00% of base) : 1023.dasm - S_P_CoreLib_System_Runtime_EH__RhRethrow
         -78 (-100.00% of base) : 1032.dasm - S_P_CoreLib_System_Runtime_EH_ExInfo__Init
         -65 (-100.00% of base) : 1016.dasm - RhpEHEnumInitFromStackFrameIterator
         -60 (-100.00% of base) : 1000.dasm - RuntimeInstance::GetClasslibFunctionFromCodeAddress(void*, ClasslibFunctionId)
         -44 (-100.00% of base) : 1019.dasm - RhpSetThreadDoNotTriggerGC

51 total methods with Code Size differences (45 improved, 6 regressed)

The -O1 change excises yet more code by making Emscripten link-in the "release" version of its standard libraries.

Summary of Code Size diffs:
(Lower is better)

Total bytes of base: 669465
Total bytes of diff: 659909
Total bytes of delta: -9556 (-1.43% % of base)
Average relative delta: -2.81%
    diff is an improvement
    average relative diff is an improvement

Top method improvements (percentages):
         -78 (-89.66% of base) : 1030.dasm - abort_message
          -3 (-11.54% of base) : 1000.dasm - __wasm_call_ctors

Top methods only present in base:
       -3376 (-100.00% of base) : 1020.dasm - fmt_fp
       -2548 (-100.00% of base) : 1011.dasm - printf_core
        -570 (-100.00% of base) : 1014.dasm - pop_arg
        -504 (-100.00% of base) : 1009.dasm - __trunctfdf2
        -403 (-100.00% of base) : 1010.dasm - __vfprintf_internal
        -300 (-100.00% of base) : 1004.dasm - wcrtomb
        -229 (-100.00% of base) : 1002.dasm - memchr
        -164 (-100.00% of base) : 1023.dasm - __overflow
        -146 (-100.00% of base) : 1006.dasm - frexp
        -136 (-100.00% of base) : 1017.dasm - fmt_u
        -132 (-100.00% of base) : 1026.dasm - locking_putc
        -132 (-100.00% of base) : 1018.dasm - pad
        -123 (-100.00% of base) : 1025.dasm - do_putc
        -123 (-100.00% of base) : 1013.dasm - getint
         -83 (-100.00% of base) : 1007.dasm - __ashlti3
         -83 (-100.00% of base) : 1008.dasm - __lshrti3
         -64 (-100.00% of base) : 1015.dasm - fmt_x
         -54 (-100.00% of base) : 1016.dasm - fmt_o
         -49 (-100.00% of base) : 1021.dasm - pop_arg_long_double
         -32 (-100.00% of base) : 1031.dasm - emscripten_stack_init

36 total methods with Code Size differences (36 improved, 0 regressed)

Contributes to #3132.
Contributes to #2169.

[SingleAccretion]

@dotnet/nativeaot-llvm

[yowl]

Thanks, looks good!