RFR: 8329430: MetaspaceShared::preload_and_dump should clear pending exception

[Calvin Cheung]

Please review this simple fix for clearing the pending exception in `MetaspaceShared::preload_and_dump()`.

Passed tiers 1 - 4 testing.

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Commit messages:
 - 8329430: MetaspaceShared::preload_and_dump should clear pending exception

Changes: https://git.openjdk.org/jdk/pull/18777/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18777&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8329430
  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18777.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18777/head:pull/18777

PR: https://git.openjdk.org/jdk/pull/18777