Fix sanitizer failure

I added the insertion point guard "just to be safe" and never removed
it. There isn't insertion point guarding on the other route out of this
function and we do not preserve the insertion point around getFiniBB
either so it is not needed here.

The problem flagged by the sanitizers was because the saved insertion
point pointed to an instruction which was then removed inside the FiniCB
for some clang codegen functions. The instruction was freed when it was
removed. Then accessing it to restore the insertion point was a use
after free bug.

Author: tblah

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

@@ -701,7 +701,7 @@ Error OpenMPIRBuilder::FinalizationInfo::mergeFiniBB(IRBuilderBase &Builder,
   // Simple case: FiniBB does not exist yet: re-use OtherFiniBB.
   if (!FiniBB) {
     FiniBB = OtherFiniBB;
-    IRBuilderBase::InsertPointGuard Guard(Builder);
+
     Builder.SetInsertPoint(FiniBB->getFirstNonPHIIt());
     if (Error Err = FiniCB(Builder.saveIP()))
       return Err;