[NFC] Refactor the Preprocessor function that handles Macro definitions and rename Arguments to Parameters in Macro Definitions. 
  - Extracted the reading of the tokens out into a separate function.
  - Replace 'Argument' with 'Parameter' when referring to the identifiers of the macro definition (as opposed to the supplied arguments - MacroArgs - during the macro invocation).

This is in preparation for submitting patches for review to implement __VA_OPT__ which will otherwise just keep lengthening the HandleDefineDirective function and making it less comprehensible.


Thanks!

llvm-svn: 308157
diff --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
index 236f264..869aeac 100644
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -8195,7 +8195,7 @@
     return nullptr;
 
   // Check that the identifier is not one of the macro arguments.
-  if (std::find(MI->arg_begin(), MI->arg_end(), &II) != MI->arg_end())
+  if (std::find(MI->param_begin(), MI->param_end(), &II) != MI->param_end())
     return nullptr;
 
   MacroDirective *InnerMD = PP.getLocalMacroDirectiveHistory(&II);