[ms] [llvm-ml] Fix parity errors in error handling for INCLUDE directive

[epastor]

Summary

Also adds basic testing for "include" directive.

llvm/lib/MC/MCParser/MasmParser.cpp

 /// parseDirectiveInclude
 ///  ::= include <filename>
 ///    | include filename
 bool MasmParser::parseDirectiveInclude() {
   // Allow the strings to have escaped octal character sequence.
   std::string Filename;
   SMLoc IncludeLoc = getTok().getLoc();
 
-  if (!parseAngleBracketString(Filename))
+  if (parseAngleBracketString(Filename))
     Filename = parseStringTo(AsmToken::EndOfStatement);
-  if (check(!Filename.empty(), "missing filename in 'include' directive") ||
+  if (check(Filename.empty(), "missing filename in 'include' directive") ||
       check(getTok().isNot(AsmToken::EndOfStatement),
             "unexpected token in 'include' directive") ||
       // Attempt to switch the lexer to the included file before consuming the
       // end of statement to avoid losing it when we switch.
       check(enterIncludeFile(Filename), IncludeLoc,
             "Could not find include file '" + Filename + "'"))
     return true;
 

llvm/test/tools/llvm-ml/include.asm

+# RUN: llvm-ml -filetype=s %s /I %S /Fo - | FileCheck %s
+
+include included.inc
+
+.code
+
+t1:
+mov eax, Const
+
+; CHECK-LABEL: t1:
+; CHECK-NEXT: mov eax, 8
+
+t2:
+push_pop ebx
+
+; CHECK-LABEL: t2:
+; CHECK-NEXT: push ebx
+; CHECK-NEXT: pop ebx
+
+end

llvm/test/tools/llvm-ml/included.inc

+Const equ 00008H
+
+push_pop macro Reg
+  push Reg
+  pop Reg
+endm