8254973: CompletableFuture.ThreadPerTaskExecutor does not throw NPE in #execute
------------- Commit messages: - JDK-8254973 Changes: https://git.openjdk.java.net/jdk/pull/2018/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2018&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8254973 Stats: 5 lines in 1 file changed: 4 ins; 0 del; 1 mod Patch: https://git.openjdk.java.net/jdk/pull/2018.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/2018/head:pull/2018 PR: https://git.openjdk.java.net/jdk/pull/2018
