[jdk17] RFR: 8268591: a few runtime/jni tests don't need `/othervm`

[Igor Ignatyev]

Hi all,

could you please review this small and trivial patch that removes `/othervm` from 3 `runtime/jni` tests?
from JBS:
> `runtime/jni/registerNativesWarning/TestRegisterNativesWarning.java`, `checked/TestCheckedEnsureLocalCapacity.java`, and `atExit/TestAtExit.java` use `main/othervm` whereas in fact, they don't need `othervm`, and if we had CODETOOLS-7902658 implemented, they would have used `driver` mode. this RFE is to remove `/othervm`, so we at least won't waste time on creating a fresh JVM.

the patch explicitly sets `-Djava.library.path=` for the child processes so they are able to locate native libraries.

testing: `runtime/jni` on `{linux,windows,macosx}-x64`

Thanks,
-- Igor

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Commit messages:
 - copyright
 - 8268591

Changes: https://git.openjdk.java.net/jdk17/pull/18/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk17&pr=18&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268591
  Stats: 18 lines in 3 files changed: 8 ins; 1 del; 9 mod
  Patch: https://git.openjdk.java.net/jdk17/pull/18.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17 pull/18/head:pull/18

PR: https://git.openjdk.java.net/jdk17/pull/18