RFR: 8370730: Test serviceability/attach/EarlyDynamicLoad/EarlyDynamicLoad.java needs to be resilient about warnings

[Francesco Andreuzzi]

Before [JDK-8359472](https://bugs.openjdk.org/browse/JDK-8359472), the JVM would crash with an assertion failure during the test. So the check was supposed to check for the presence of something like:

#
# A fatal error has been detected by the Java Runtime Environment:
#
....


However, checking the exit code is enough in this case.

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

Commit messages:
 - nn
 - ignore vm warning

Changes: https://git.openjdk.org/jdk/pull/28017/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28017&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8370730
  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/28017.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28017/head:pull/28017

PR: https://git.openjdk.org/jdk/pull/28017