RFR 8025937: assert(existing_f1 == NULL || existing_f1 == f1) failed: illegal field,change

[Coleen Phillmore]

Summary: Create extra constant pool cache entries for 
invokespecial/InterfaceMethodref to hold the alternate resolution.

open webrev at http://cr.openjdk.java.net/~coleenp/8025937/
bug link https://bugs.openjdk.java.net/browse/JDK-8025937

Tested with testcase in time api, java/lang/invoke jtreg tests, NSK 
mlvm, quick and defmeth tests, jck lang/vm tests, and testcase in changeset.

Thanks,
Coleen