Rework the core of class parsing/runtime semantic (#3598)

Changes:
 - Use the pre-scanner to provide information for the parser about the existence of the class constructor
 - The allocation of the super declarative environment is no longer needed
 - The VM frame context holds the information about the this binding status
 - Reduce the number of class related VM/CBC instructions
 - Improve ecma_op_function_{construct, call} to properly set new.target

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

jerry-core/parser/js/js-scanner.h

@@ -46,6 +46,7 @@ typedef enum
   SCANNER_TYPE_CASE, /**< case statement */
 #if ENABLED (JERRY_ES2015)
   SCANNER_TYPE_INITIALIZER, /**< destructuring binding or assignment pattern with initializer */
+  SCANNER_TYPE_CLASS_CONSTRUCTOR, /**< class constructor */
   SCANNER_TYPE_LET_EXPRESSION, /**< let expression */
   SCANNER_TYPE_ERR_REDECLARED, /**< syntax error: a variable is redeclared */
 #endif /* ENABLED (JERRY_ES2015) */