Implement BigInt primitve type and some of its operations (#4062)

Supported operations:
- parse BigInt (decimal, hexadecimal, binary)
- toString with any radix between 2 and 36
- arithmetic operations: negate, add, subtract, multiply, divide, modulo
- left and right shift

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

jerry-core/ecma/operations/ecma-objects.c

@@ -2648,6 +2648,12 @@ ecma_object_get_class_name (ecma_object_t *obj_p) /**< object */
             return LIT_MAGIC_STRING_FUNCTION_UL;
           }
 #endif /* ENABLED (JERRY_BUILTIN_PROXY) */
+#if ENABLED (JERRY_BUILTIN_BIGINT)
+          case ECMA_BUILTIN_ID_BIGINT:
+          {
+            return LIT_MAGIC_STRING_FUNCTION_UL;
+          }
+#endif /* ENABLED (JERRY_BUILTIN_BIGINT) */
           default:
           {
             JERRY_ASSERT (ecma_object_check_class_name_is_object (obj_p));