Remove the WarnMissedTransformations pass from the 1.10 pipeline (#55377

)

Backport of #54871 onto 1.10

We don't have the luxury of modifying the C-API. This pass surfaces LLVM
missed transformation warnings,
which is surprising to users. It can be very helpful, but it can also
add unactionable noise to the output
of Julia programs.

This PR simply removes it from the pipeline.

src/pipeline.cpp

@@ -72,7 +72,6 @@
 #include <llvm/Transforms/Scalar/SROA.h>
 #include <llvm/Transforms/Scalar/SimpleLoopUnswitch.h>
 #include <llvm/Transforms/Scalar/SimplifyCFG.h>
-#include <llvm/Transforms/Scalar/WarnMissedTransforms.h>
 #include <llvm/Transforms/Utils/InjectTLIMappings.h>
 #include <llvm/Transforms/Vectorize/LoopVectorize.h>
 #include <llvm/Transforms/Vectorize/SLPVectorizer.h>
@@ -568,7 +567,6 @@ static void buildPipeline(ModulePassManager &MPM, PassBuilder *PB, OptimizationL
         if (O.getSpeedupLevel() >= 2) {
             buildVectorPipeline(FPM, PB, O, options);
         }
-        FPM.addPass(WarnMissedTransformationsPass());
         MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
     }
     buildIntrinsicLoweringPipeline(MPM, PB, O, options);