RFR: 8271323: [TESTBUG] serviceability/sa/ClhsdbCDSCore.java fails with -XX:TieredStopAtLevel=1

[Nick Gasson]

This test fails reliably with `-XX:TieredStopAtLevel=1` since JDK-8251462. MDOs are no longer allocated in this mode so the clhsdb `printmdo -a` command prints nothing.  The failure is basically the same as JDK-8236042 which happened with `-Xcomp -XX:TieredStopAtLevel=1` so the workaround for that just needs to be adjusted slightly.

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Commit messages:
 - 8271323: [TESTBUG] serviceability/sa/ClhsdbCDSCore.java fails with -XX:TieredStopAtLevel=1

Changes: https://git.openjdk.java.net/jdk/pull/4910/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4910&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8271323
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4910.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4910/head:pull/4910

PR: https://git.openjdk.java.net/jdk/pull/4910