Simplify ecma_builtin_date_parse function (#3280)

This PR is the preparation of the #2946 issue.
(Date.parse() should handle UTC date string format)

Changes:
- Handle min/max values in ecma_date_parse_date_chars function instead of code duplication
- Parse special characters in the new ecma_date_parse_special_char function
- Additionally fixed two parsing issue: invalid formats should be refused

JerryScript-DCO-1.0-Signed-off-by: Csaba Osztrogonác oszi@inf.u-szeged.hu

tests/jerry/date-parse.js

@@ -59,7 +59,9 @@ var wrongFormats = ["",
                     "-02015-01-01",
                     "002015-01-01",
                     "+0002015-01-01",
-                    "-0002015-01-01"];
+                    "-0002015-01-01",
+                    "2015-01T00:00:00.000-03X00",
+                    "2015-01-01T00-03:00"];
 
 for (i in wrongFormats) {
   var d = Date.parse(wrongFormats[i]);