RFR: 8293201: Library detection in runtime/ErrorHandling/TestDwarf.java fails on some systems

[Aleksey Shipilev]

When building x86_32 on Ubuntu 22.04, the test fails to find the library name in `"C  [libc.so.6+0x85ff1]"`, because the regexp seems too broad. Since we are matching with the unanchored regexp, we can just try and find the smaller prefix, which still matches the library name.

But the original regexp seems odd to begin with. Why do we match `0x` twice? Why do we have the escaped `\[`, followed by trailing `]` (the last one in the patch now), which is not escaped? This is a question for you, @chhagedorn :)

Additional testing:
 - [x] Ubuntu 22.04 x86_32 build

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Commit messages:
 - Fix

Changes: https://git.openjdk.org/jdk/pull/10113/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10113&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8293201
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/10113.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10113/head:pull/10113

PR: https://git.openjdk.org/jdk/pull/10113