switch the macroinfo argument lists from being allocated off the heap
to being allocated from the same bumpptr that the MacroInfo objects 
themselves are.

This speeds up -Eonly cocoa.h pth by ~4%, fsyntax-only is barely measurable.

llvm-svn: 65195
diff --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
index a85b5db..ccb179d 100644
--- a/clang/lib/Lex/Preprocessor.cpp
+++ b/clang/lib/Lex/Preprocessor.cpp
@@ -101,7 +101,7 @@
     // will be released when the BumpPtrAllocator 'BP' object gets
     // destroyed. We still need to run the dstor, however, to free
     // memory alocated by MacroInfo.
-    I->second->Destroy();
+    I->second->Destroy(BP);
     I->first->setHasMacroDefinition(false);
   }