[NFC] Fix evaluation order dependency in call arguments

The code assumes parseRegister() executes before the standalone SRegLoc
argument to check(). Since function arguments are indeterminately sequenced
per C++17 [expr.call]/5, check() may receive a null location instead of
the actual parsed source location.

Detected by the CFamily analyzer for SonarQube.
https://docs.sonarsource.com/sonarqube-cloud/advanced-setup/languages/c-family/overview/

Author: michael-jabbour-sonarsource

llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp

@@ -11788,9 +11788,8 @@ bool ARMAsmParser::parseDirectiveReq(StringRef Name, SMLoc L) {
   Parser.Lex(); // Eat the '.req' token.
   MCRegister Reg;
   SMLoc SRegLoc, ERegLoc;
-  if (check(parseRegister(Reg, SRegLoc, ERegLoc), SRegLoc,
-            "register name expected") ||
-      parseEOL())
+  const bool parseResult = parseRegister(Reg, SRegLoc, ERegLoc);
+  if (check(parseResult, SRegLoc, "register name expected") || parseEOL())
     return true;
 
   if (RegisterReqs.insert(std::make_pair(Name, Reg)).first->second != Reg)