RFR: 8208237: Re-examine defmeth tests and update as needed

[Mikhailo Seledtsov]

On Wed, 5 May 2021 10:38:18 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

> Some test cleanups:
> - removed all `@KnownFailure`
> - narrowed expected error types in some cases
> - fixed private method invocation tests in reflection mode (got rid of `NoSuchMethodError`s in reflection mode)
> - introduced `TesterBuilder::new_()` to let the tests precisely describe the intent
> - some other minor cleanups
> 
> Testing:
> - [x] defmeth tests
> - [x] hs-tier5 - hs-tier6 (include defmeth tests)

Change looks good to me. Thanks for doing it.

-------------

PR: https://git.openjdk.java.net/jdk/pull/3879