Update parser early return type in ESNEXT (#3742)

This patch updates the early return types in the parser to SyntaxError instead of ReferenceError
in ESNEXT

This patch also includes a lot of tests for LeftHandSideExpression validation when using the = operator

JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu

tests/jerry/es.next/regression-test-issue-3845.js

@@ -16,6 +16,6 @@ try {
   eval(`typeof (a) = 1 === 'undefined';`);
   assert(false);
 } catch (e) {
-  assert(e instanceof ReferenceError);
+  assert(e instanceof SyntaxError);
 }