Revert "[CodeGen] Expose the extensibility of PassConfig to plugins" (#147947)

Reverts #139059

This broke
https://lab.llvm.org/buildbot/#/builders/10/builds/9125/steps/8/logs/stdio

The bot does a SHARED_LIBS=ON build. I can reproduce locally with the
CMake cache file in offload/cmake/caches/AMDGPUBot.cmake as the build
config.

Author: jplehr

llvm/docs/WritingAnLLVMPass.rst

@@ -442,28 +442,6 @@ in certain circumstances (such as calling the ``Pass::dump()`` from a
 debugger), so it should only be used to enhance debug output, it should not be
 depended on.
 
-Scheduling a MachineFunctionPass
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-Backends create a ``TargetPassConfig`` and use ``addPass`` to schedule
-``MachineFunctionPass``\ es. External plugins can register a callback to modify
-and insert additional passes:
-
-.. code-block:: c++
-
-  RegisterTargetPassConfigCallback X{[](auto &TM, auto &PM, auto *TPC) {
-    TPC->insertPass(/* ... */);
-    TPC->substitutePass(/* ... */);
-  }};
-
-Note that passes still have to be registered:
-
-.. code-block:: c++
-
-  __attribute__((constructor)) static void initCodeGenPlugin() {
-    initializeExamplePass(*PassRegistry::getPassRegistry());
-  }
-
 .. _writing-an-llvm-pass-interaction:
 
 Specifying interactions between passes

llvm/include/llvm/Target/RegisterTargetPassConfigCallback.h

@@ -30,7 +30,6 @@
 #include "llvm/MC/TargetRegistry.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FormattedStream.h"
-#include "llvm/Target/RegisterTargetPassConfigCallback.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 using namespace llvm;
@@ -123,7 +122,6 @@ addPassesToGenerateCode(CodeGenTargetMachineImpl &TM, PassManagerBase &PM,
   PassConfig->setDisableVerify(DisableVerify);
   PM.add(PassConfig);
   PM.add(&MMIWP);
-  invokeGlobalTargetPassConfigCallbacks(TM, PM, PassConfig);
 
   if (PassConfig->addISelPasses())
     return nullptr;

llvm/lib/CodeGen/CodeGenTargetMachineImpl.cpp

@@ -3,7 +3,6 @@ list(APPEND LLVM_COMMON_DEPENDS intrinsics_gen)
 list(APPEND LLVM_TABLEGEN_FLAGS -I ${LLVM_MAIN_SRC_DIR}/lib/Target)
 
 add_llvm_component_library(LLVMTarget
-  RegisterTargetPassConfigCallback.cpp
   Target.cpp
   TargetLoweringObjectFile.cpp
   TargetMachine.cpp