Checking for anonymous class should check for NULL as well as potential nesting

The following 3 is_anonymous() invocations should be cleaned up:

- classfile/verifier.cpp - is_anonymous() is checked twice in ClassVerifier::verify_invoke_instructions().

- interpreter/linkResolver.cpp - is_anonymous() called once within
  LinkResolver::linktime_resolve_special_method().

Tasks:
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cleanup item #1 - is_anonymous() checks a bit, so we should also sanity check if host_klass() == NULL
                          before dereferencing

cleanup item #2 - these 3 code instances should also be walking up through potentially nested anonymous classes. Need more test cases of nested anonymous classes. See code in runtime/reflection.cpp, Reflection::verify_field_access() for code example that walks up through nested anonymous classes. This code came in via JDK-8027458.