[LegacyPM] Clean up includes in LowerExpectIntrinsicPass

This is a follow up to commit 8511ade which removed
legacy PM support in LowerExpectIntrinsicPass. That commit made some
of the includes redundant.

Author: bjope

llvm/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp

@@ -20,10 +20,7 @@
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/MDBuilder.h"
-#include "llvm/InitializePasses.h"
-#include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
-#include "llvm/Transforms/Scalar.h"
 #include "llvm/Transforms/Utils/MisExpect.h"
 
 #include <cmath>