RFR 8155771: [JVMCI] expose JVM_ACC_IS_CLONEABLE_FAST

[Tom Rodriguez]

http://cr.openjdk.java.net/~never/8155771/webrev

The new flag JVM_ACC_IS_CLONEABLE_FAST controls whether an object can be cloned by simply performing an allocation and copying the fields. Previously all Cloneable objects were assumed to be cloneable in this way.  Add ResolvedJavaType.isAllocationCloneable to expose this notion.  Tested with Graal.

tom