Revert "[clang] Pass -clear-ast-before-backend in Clang::ConstructJob()"

This reverts commit 47eb99aa44.

This causes crashes with -print-stats: PR52193.

clang/lib/Driver/ToolChains/Clang.cpp

@@ -4660,7 +4660,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   // cleanup.
   if (!C.isForDiagnostics())
     CmdArgs.push_back("-disable-free");
-  CmdArgs.push_back("-clear-ast-before-backend");
 
 #ifdef NDEBUG
   const bool IsAssertBuild = false;

clang/lib/Interpreter/Interpreter.cpp

@@ -113,10 +113,6 @@ CreateCI(const llvm::opt::ArgStringList &Argv) {
 
   Clang->getTarget().adjust(Clang->getDiagnostics(), Clang->getLangOpts());
 
-  // Don't clear the AST before backend codegen since we do codegen multiple
-  // times, reusing the same AST.
-  Clang->getCodeGenOpts().ClearASTBeforeBackend = false;
-
   return std::move(Clang);
 }