RFR: 8331987: Enhance stacktrace clarity for CompletableFuture CancellationException

[Viktor Klang]

This change adds wrapping of the CancellationException produced by CompletableFuture::get() and CompletableFuture::join() to add more diagnostic information and align better with FutureTask.

Running the sample code from the JBS issue in JShell will produce the following:


jshell> java.util.concurrent.CancellationException: 
	at java.base/java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:392)
	at java.base/java.util.concurrent.CompletableFuture.get(CompletableFuture.java:2073)
	at REPL.$JShell$18.m2($JShell$18.java:10)
	at REPL.$JShell$17.m1($JShell$17.java:8)
	at REPL.$JShell$16B.lambda$main$0($JShell$16B.java:8)
	at java.base/java.lang.Thread.run(Thread.java:1575)
Caused by: java.util.concurrent.CancellationException
	at java.base/java.util.concurrent.CompletableFuture.cancel(CompletableFuture.java:2510)
	at REPL.$JShell$16B.lambda$main$1($JShell$16B.java:11)
	... 1 more

-------------

Commit messages:
 - Make it possible to customize the message when wrapping a CancellationException
 - Adding wrapping of CompletableFuture CancellationExceptions from get() and join() to add diagnostic information

Changes: https://git.openjdk.org/jdk/pull/19219/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19219&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331987
  Stats: 29 lines in 3 files changed: 25 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/19219.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19219/head:pull/19219

PR: https://git.openjdk.org/jdk/pull/19219