Addresses the situation where exceptional completion of `orTimeout`:ed CompletableFutures wouldn't cancel the timeout task which could lead to memory leaks if done frequently enough with long enough timeout durations.
Fix discussed with @DougLea ------------- Commit messages: - Adding a regression test for 8303742 - Addressing JDK-8303742 by removing the check for a null exception in Canceller Changes: https://git.openjdk.org/jdk/pull/13059/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13059&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8303742 Stats: 50 lines in 2 files changed: 49 ins; 0 del; 1 mod Patch: https://git.openjdk.org/jdk/pull/13059.diff Fetch: git fetch https://git.openjdk.org/jdk pull/13059/head:pull/13059 PR: https://git.openjdk.org/jdk/pull/13059
