RFR: 8283010: serviceability/sa/ClhsdbThread.java failed with "'Base of Stack:' missing from stdout/stderr "

[Chris Plummer]

Each time you attach to a target JVM on Windows, thread Id's can change (although they rarely do). For this reason you can't reliably do what this test is doing, which is attach, run jstack to get the threadId of a thread, detach, attach again and run the `thread` command using the threadId. It might not be valid any more. For this reason I am changing the test to ignore the result of the `thread` command when running on windows. This is the same fix as was done for [JDK-8280770](https://bugs.openjdk.org/browse/JDK-8280770)

I'd like to push this as a trivial change.

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Commit messages:
 - Ignore results on windows

Changes: https://git.openjdk.org/jdk/pull/10185/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10185&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8283010
  Stats: 13 lines in 1 file changed: 8 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/10185.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10185/head:pull/10185

PR: https://git.openjdk.org/jdk/pull/10185