Revert r192758 (and r192759), "MC: Better handling of tricky symbol and section names"

GNU AS didn't like quotes in symbol names.

    Error: junk at end of line, first unrecognized character is `"'

        .def "@feat.00";
        "@feat.00" = 1

Reproduced on Cygwin's 2.23.52.20130309 and mingw32's 2.20.1.20100303.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192775 91177308-0d34-0410-b5e6-96231b3b80d8

lib/MC/MCParser/COFFAsmParser.cpp

@@ -295,7 +295,12 @@ bool COFFAsmParser::ParseSectionSwitch(StringRef Section,
 }
 
 bool COFFAsmParser::ParseSectionName(StringRef &SectionName) {
-  return getParser().parseIdentifier(SectionName);
+  if (!getLexer().is(AsmToken::Identifier))
+    return true;
+
+  SectionName = getTok().getIdentifier();
+  Lex();
+  return false;
 }
 
 // .section name [, "flags"]