RFR: 8280820: Clean up bug8033699 and bug8075609.java tests: regtesthelpers aren't used

Sat Feb 5 18:16:04 UTC 2022

On Wed, 2 Feb 2022 13:38:36 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

> Removed references to `regtesthelpers` libarary which isn't used.
> Organised imports and replaced anonymous classes with lambda expressions.
> 
> Put `waitForIdle` before the test execution starts and moved the frame to the centre of the screen.
> 
> The CI with the updated tests is green.

Marked as reviewed by prr (Reviewer).

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PR: https://git.openjdk.java.net/jdk/pull/7322