Correctly handle the Proxy IsCallable and IsConstructor information (#4264)

The `IsCallable(target)` and `IsConstructor(target)` info
can't be stored in the target/handler values.
If the input for the ProxyCreate was a revocable Proxy the original target's
callable/constructor information must be retained even after the
Proxy was revoked.

JerryScript-DCO-1.0-Signed-off-by: Peter Gal pgal.usz@partner.samsung.com

jerry-core/ecma/base/ecma-globals.h

@@ -2128,6 +2128,10 @@ do \
 #if ENABLED (JERRY_BUILTIN_PROXY)
 /**
  * Description of Proxy objects.
+ *
+ * A Proxy object's property list is used to store extra information:
+ *  * The "header.u1.property_list_cp" 1st tag bit stores the IsCallable information.
+ *  * The "header.u1.property_list_cp" 2nd tag bit stores the IsConstructor information.
  */
 typedef struct
 {