Clean up assembly statement separator support.

The MC asm lexer wasn't honoring a non-default (anything but ';') statement
separator. Fix that, and generalize a bit to support multi-character
statement separators.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128227 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCParser/AsmLexer.h

@@ -49,6 +49,7 @@ public:
   virtual StringRef LexUntilEndOfStatement();
 
   bool isAtStartOfComment(char Char);
+  bool isAtStatementSeparator(const char *Ptr);
 
   const MCAsmInfo &getMAI() const { return MAI; }