System.identityHashCode() no longer needs a TruffleBoundary

* It used to be needed on SubstrateVM, but not anymore.

(cherry picked from commit 55171c9)

Author: eregon

src/main/java/org/truffleruby/core/kernel/KernelNodes.java

@@ -965,19 +965,16 @@ protected long hashBignum(RubyBignum value) {
             return HashOperations.hashBignum(value, getContext(), this);
         }
 
-        @TruffleBoundary
         @Specialization
         protected int hash(Nil self) {
             return System.identityHashCode(self);
         }
 
-        @TruffleBoundary
         @Specialization
         protected int hashEncoding(RubyEncoding self) {
             return System.identityHashCode(self);
         }
 
-        @TruffleBoundary
         @Specialization(guards = "!isRubyBignum(self)")
         protected int hash(RubyDynamicObject self) {
             return System.identityHashCode(self);

src/main/java/org/truffleruby/debug/TruffleDebugNodes.java

@@ -549,13 +549,11 @@ public abstract static class ForeignObjectNode extends CoreMethodArrayArgumentsN
 
         @ExportLibrary(InteropLibrary.class)
         public static class ForeignObject implements TruffleObject {
-            @TruffleBoundary
             @ExportMessage
             protected TriState isIdenticalOrUndefined(Object other) {
                 return other instanceof ForeignObject ? TriState.valueOf(this == other) : TriState.UNDEFINED;
             }
 
-            @TruffleBoundary
             @ExportMessage
             protected int identityHashCode() {
                 return System.identityHashCode(this);
@@ -567,7 +565,6 @@ protected String toDisplayString(boolean allowSideEffects) {
             }
         }
 
-        @TruffleBoundary
         @Specialization
         protected Object foreignObject() {
             return new ForeignObject();