[ARM] Add doFinalization() to ARMCodeGenPrepare pass.

Attempt to fix the leak introduced in r337687 and make sanitizer
buildbots green again.

llvm-svn: 337709
diff --git a/llvm/lib/Target/ARM/ARMCodeGenPrepare.cpp b/llvm/lib/Target/ARM/ARMCodeGenPrepare.cpp
index a450b15..39b9813 100644
--- a/llvm/lib/Target/ARM/ARMCodeGenPrepare.cpp
+++ b/llvm/lib/Target/ARM/ARMCodeGenPrepare.cpp
@@ -108,6 +108,7 @@
 
   bool doInitialization(Module &M) override;
   bool runOnFunction(Function &F) override;
+  bool doFinalization(Module &M) override;
 };
 
 }
@@ -734,6 +735,11 @@
   return MadeChange;
 }
 
+bool ARMCodeGenPrepare::doFinalization(Module &M) {
+  delete Promoter;
+  return false;
+}
+
 INITIALIZE_PASS_BEGIN(ARMCodeGenPrepare, DEBUG_TYPE,
                       "ARM IR optimizations", false, false)
 INITIALIZE_PASS_END(ARMCodeGenPrepare, DEBUG_TYPE, "ARM IR optimizations",