RFR (L) JDK-8209301: JVM rename is_anonymous, host_klass to unsafe specific terminology ahead of Unsafe.defineAnonymousClass deprecation

[Lois Foltan]

Ahead of the work to support a new MethodHandle.Lookup functionality to 
define an anonymous or other class within the context of a hosted class, 
(see JDK-8171335), please review this clean up to use the terminology of 
"is_unsafe_anonymous" instead of "is_anonymous" for classes defined to 
the VM via Unsafe.defineAnonymousClass.  InstanceKlass' "host_klass" 
method has also been renamed to "unsafe_anonymous_host" in order to 
avoid confusion with "nest_host".  It is not anticipated that 
JDK-8171335 work will use the same "anonymous" terminology.

open webrev at http://cr.openjdk.java.net/~lfoltan/bug_jdk8209301/webrev/
bug link at https://bugs.openjdk.java.net/browse/JDK-8209301

Testing: hs-tier1-4, jdk-tier1-3 (complete)
                hs-tier4-5 (in progress)

Thanks,
Lois