RFR: 8375742: Test java/lang/invoke/MethodHandleProxies/Driver.java does not run Unnamed.java

[Chen Liang]

This test program `Unnamed` ran from `java/lang/invoke/MethodHandleProxies/Driver.java` is incorrectly run by testng, which does nothing. It is intended to be a main test. The conversion reveals the test itself has some problems as well, also fixed within this patch.

Testing: This test itself. This change is test-only.

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

Commit messages:
 - 8375742

Changes: https://git.openjdk.org/jdk/pull/29330/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29330&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8375742
  Stats: 6 lines in 2 files changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/29330.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29330/head:pull/29330

PR: https://git.openjdk.org/jdk/pull/29330