RFR: 8365098: make/RunTests.gmk generates a wrong path to test artifacts on Alpine

[Roman Marchenko]

This change fixes the test artifact path on Alpine as `'[_*1000]'` is not recognized as a correct pattern, at least on Alpine 3.11.
BTW I'm not sure what `[_*1000]` is supposed to do, I guess it doesn't work as expected, regardless it's ok on most Linux.

Without this fix, on Alpine the command `make test-prebuilt` generated paths like the following:

Test report is stored in build/run-test-prebuilt/test-results/jtreg]test]hotspot]jtreg]tier1]common


Now it looks better:

Test report is stored in build/run-test-prebuilt/test-results/jtreg_test_hotspot_jtreg_tier1_common

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Commit messages:
 - 8365098: make/RunTests.gmk generates a wrong path to test artifacts on Alpine

Changes: https://git.openjdk.org/jdk/pull/26742/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26742&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365098
  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/26742.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26742/head:pull/26742

PR: https://git.openjdk.org/jdk/pull/26742