RFR: 8303921: serviceability/sa/UniqueVtableTest.java timed out [v2]

[Alex Menkov]

> The change:
> - updates UniqueVtableTest to follow standard SA way - attach to target from subprocess and use SATestUtils.addPrivilegesIfNeeded for the subprocess;
> - updates several tests in the same directory to resolve NoClassDefFoundError failures; It's known JTReg issue that "@build" actions for part of used shared classes may cause intermittent NoClassDefFoundError in other tests which use the same shared library classpath.
> 
> Tested: 100 runs on all platforms, no failures

Alex Menkov has updated the pull request incrementally with one additional commit since the last revision:

  feedback

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13030/files
  - new: https://git.openjdk.org/jdk/pull/13030/files/69cc6dae..0e8573d8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13030&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13030&range=00-01

  Stats: 5 lines in 1 file changed: 2 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/13030.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/13030/head:pull/13030

PR: https://git.openjdk.org/jdk/pull/13030