hg: valhalla/valhalla: Add utility methods for substitutability tests for VM to experiment acmp for values.

[mandy.chung at oracle.com]

Changeset: a0ee83b59f56
Author:    mchung
Date:      2018-12-14 11:50 -0800
URL:       http://hg.openjdk.java.net/valhalla/valhalla/rev/a0ee83b59f56

Add utility methods for substitutability tests for VM to experiment acmp for values.

! src/java.base/share/classes/java/lang/invoke/ValueBootstrapMethods.java
+ test/jdk/valhalla/valuetypes/SubstitutabilityTest.java
+ test/jdk/valhalla/valuetypes/Value.java