Revert "[Assignment Tracking][7/*] Add assignment tracking functionality to clang"

This reverts commit 28f9636.

Bot failure: https://lab.llvm.org/buildbot/#/builders/109/builds/50251

Author: OCHyams

clang/lib/CodeGen/BackendUtil.cpp

@@ -30,7 +30,6 @@
 #include "llvm/CodeGen/SchedulerRegistry.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/IR/DataLayout.h"
-#include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Module.h"
@@ -831,13 +830,6 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
   SI.registerCallbacks(PIC, &FAM);
   PassBuilder PB(TM.get(), PTO, PGOOpt, &PIC);
 
-  if (CodeGenOpts.EnableAssignmentTracking) {
-    PB.registerPipelineStartEPCallback(
-        [&](ModulePassManager &MPM, OptimizationLevel Level) {
-          MPM.addPass(AssignmentTrackingPass());
-        });
-  }
-
   // Enable verify-debuginfo-preserve-each for new PM.
   DebugifyEachInstrumentation Debugify;
   DebugInfoPerPass DebugInfoBeforePass;