Introduce a new token kind 'cxx_defaultarg_end' to mark the end of C++ default argume...

Introduce a new token kind 'cxx_defaultarg_end' to mark the end of C++ default arguments that were part of
lexed method declarations.

This avoid interference with tokens coming after the point where the default arg tokens were 'injected', e.g. for

typedef struct Inst {
  void m(int x=0);
} *InstPtr;

when parsing '0' the next token would be '*' and things would be messed up.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@110436 91177308-0d34-0410-b5e6-96231b3b80d8