audit use of err_expected_after

the order of the parameters is switched as opposed to either and this
was not caught in the unit tests

Author: inbelic

clang/lib/Parse/ParseHLSLRootSignature.cpp

@@ -1299,9 +1299,11 @@ bool RootSignatureParser::consumeExpectedToken(TokenKind Expected,
     DB << Expected;
     break;
   case diag::err_expected_either:
-  case diag::err_expected_after:
     DB << Expected << Context;
     break;
+  case diag::err_expected_after:
+    DB << Context << Expected;
+    break;
   default:
     break;
   }

clang/test/SemaHLSL/RootSignature-err.hlsl

@@ -55,3 +55,15 @@ void bad_root_signature_10() {}
 // expected-error@+1 {{invalid parameter of DescriptorTable}}
 [RootSignature("DescriptorTable(invalid))")]
 void bad_root_signature_11() {}
+
+// expected-error@+1 {{expected integer literal after '+'}}
+[RootSignature("CBV(space = +invalid))")]
+void bad_root_signature_12() {}
+
+// expected-error@+1 {{expected integer literal after '='}}
+[RootSignature("CBV(space = invalid))")]
+void bad_root_signature_13() {}
+
+// expected-error@+1 {{expected '(' after UAV}}
+[RootSignature("UAV invalid")]
+void bad_root_signature_14() {}