[nfc][ctx_prof] Remove spurious #include in PGOCtxProfFlattening.cpp

Re. PR #llvm#107329, 2 includes weren't necessary - the CodeGen one, in
particular, seemed accidentally (IDE) introduced.

Author: mtrofin

llvm/lib/Transforms/Instrumentation/PGOCtxProfFlattening.cpp

@@ -22,9 +22,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/ScopeExit.h"
 #include "llvm/Analysis/CtxProfAnalysis.h"
-#include "llvm/Analysis/OptimizationRemarkEmitter.h"
 #include "llvm/Analysis/ProfileSummaryInfo.h"
-#include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/IR/Analysis.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/Dominators.h"