RFR: 8348960: [leyden] compiler/c1/TestConcurrentPatching.java is stuck [v3]

[Aleksey Shipilev]

> This is seen in GHA, and reproduces well on my machine as well:
> 
> 
> $ CONF=linux-x86_64-server-fastdebug make images test TEST=compiler/c1/TestConcurrentPatching.java
> <stuck, timeout>
> 
> 
> Test runs with `-Xcomp`. gdb "thread apply all bt" shows the compilers are idle. Supplying `-XX:-UseLockFreeCompileQueues` makes the test pass. I believe there is a bug in `UseLockFreeCompileQueues` in leyden repo. 
> 
> The comment hopefully explains what happens here. This is a corner case that seems to reproduce on the test that runs `-Xcomp` with a very few compilations.
> 
> Additional testing:
>  - [x] GHA
>  - [x] Linux x86_64 server fastdebug, `compiler/c1/TestConcurrentPatching.java`, 100x

Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:

  Move the fix to CompileTask.get

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

Changes:
  - all: https://git.openjdk.org/leyden/pull/30/files
  - new: https://git.openjdk.org/leyden/pull/30/files/1e1ec544..f8a10da9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=leyden&pr=30&range=02
 - incr: https://webrevs.openjdk.org/?repo=leyden&pr=30&range=01-02

  Stats: 38 lines in 2 files changed: 16 ins; 19 del; 3 mod
  Patch: https://git.openjdk.org/leyden/pull/30.diff
  Fetch: git fetch https://git.openjdk.org/leyden.git pull/30/head:pull/30

PR: https://git.openjdk.org/leyden/pull/30