RFR 8202913: loader constraint message for fields specifies incorrect referring class

[Harold David Seigel]

Hi,

Please review this change to correct and simplify the error message 
displayed when a loader constraint check fails when trying to access a 
field.

The old message (for this test case):

      loader constraint violation: when resolving field "_field1" the
    class loader "<unnamed>" (instance of ClassLoaderForChildGrandFoo,
    child of "app" jdk.internal.loader.ClassLoaders$AppClassLoader) of
    the referring class, Parent, and the class loader "<unnamed>"
    (instance of ClassLoaderForParentFoo, child of "app"
    jdk.internal.loader.ClassLoaders$AppClassLoader) for the field's
    resolved type, Foo, have different Class objects for that type

The new message:

    loader constraint violation: when resolving field "_field1" of type
    Foo, the class loader "<unnamed>" (instance of
    ClassLoaderForChildGrandFoo, child of "app"
    jdk.internal.loader.ClassLoaders$AppClassLoader) of the current
    class, Child, and the class loader "<unnamed>" (instance of
    ClassLoaderForParentFoo, child of "app"
    jdk.internal.loader.ClassLoaders$AppClassLoader) for the field's
    defining type, Parent, have different Class objects for type Foo

Open Webrev: http://cr.openjdk.java.net/~hseigel/bug_8202913/webrev/

JBS Bug:  https://bugs.openjdk.java.net/browse/JDK-8202913

This fix was tested with Mach5 tiers 1 and 2 tests and builds on 
Linux-X64, Windows, Solaris Sparc, and Mac OS X, with tiers 3-5 tests on 
Linux-x64, and with JCK-11 Lang and VM tests.

Thanks, Harold