[MERGE #5317 @pleath] OS#17790507: [Test262] Throw SyntaxError rather than early ReferenceError on bad LHS in for loop header

Merge pull request #5317 from pleath:invalidlhsinfor

Author: pleath

lib/Parser/Parse.cpp

@@ -9918,7 +9918,7 @@ ParseNodePtr Parser::ParseStatement()
                  ? !PHASE_OFF_RAW(Js::EarlyReferenceErrorsPhase, m_sourceContextInfo->sourceContextId, GetCurrentFunctionNode()->functionId)
                  : !PHASE_OFF1(Js::EarlyReferenceErrorsPhase)))
             {
-                Error(JSERR_CantAssignTo);
+                Error(ERRInvalidLHSInFor);
             }
 
             this->GetScanner()->Scan();

lib/Parser/perrors.h

@@ -100,3 +100,5 @@ LSC_ERROR_MSG(1086, ERRInvalidModuleImportOrExport, "Module import or export sta
 LSC_ERROR_MSG(1087, ERRInvalidExportName, "Unable to resolve module export name")
 
 LSC_ERROR_MSG(1088, ERRLetIDInLexicalDecl, "'let' is not an allowed identifier in lexical declarations")
+
+LSC_ERROR_MSG(1089, ERRInvalidLHSInFor, "Invalid left-hand side in for loop")