Properly initialize the parser_crash debug token.

Found by msan.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@231605 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Lex/Pragma.cpp

@@ -870,7 +870,9 @@ struct PragmaDebugHandler : public PragmaHandler {
       LLVM_BUILTIN_TRAP;
     } else if (II->isStr("parser_crash")) {
       Token Crasher;
+      Crasher.startToken();
       Crasher.setKind(tok::annot_pragma_parser_crash);
+      Crasher.setAnnotationRange(SourceRange(Tok.getLocation()));
       PP.EnterToken(Crasher);
     } else if (II->isStr("llvm_fatal_error")) {
       llvm::report_fatal_error("#pragma clang __debug llvm_fatal_error");