RFR: 8302152: Speed up tests with infinite loops, sleep less [v3]

[Emanuel Peter]

> From over `5 sec` to about `0.8 sec`.
> 
> I simply reduced the `Thread.sleep`.
> 
> I verified that the same compilations still happen.
> 
> ~/Documents/jtreg/bin/jtreg -va -s -jdk:/home/emanuel/Documents/fork5-jdk/build/linux-x64-debug/jdk/ -javaoptions:"-XX:CompileCommand=printcompilation,compiler.loopopts.TestInfLoopNearUsePlacement::test" /home/emanuel/Documents/fork5-jdk/open/test/hotspot/jtreg/compiler/loopopts/TestInfLoopNearUsePlacement.java
> 
>     283   32 % !   3       compiler.loopopts.TestInfLoopNearUsePlacement::test @ 39 (61 bytes)
>     284   33 % !   4       compiler.loopopts.TestInfLoopNearUsePlacement::test @ 39 (61 bytes)
>     286   34   !   4       compiler.loopopts.TestInfLoopNearUsePlacement::test (61 bytes)
> 
> 
> On the time measurement that I got initially reported, this test was flagged as especially long-running, with `17 sec`. There may well be another issue, but I hope this fix already does the trick. We will see this in a while once I get the new data.
> 
> **Update**
> Did the same for 4 more tests. Always ensured that we still have all compilations.
> 
> `TestStrangeControl.java` -> reduced from `5sec` to `2sec`. Needs sleep of `1sec` to ensure we still run all compilations as before.
> 
> `TestInfiniteLoopNest.java` -> reduced from `5sec` to `1.5sec`.
> 
> `TestInfiniteLoopCCP.java` -> reduced from `4.5sec` to `0.8sec`.
> 
> `TestCMoveWithDeadPhi.java` -> reduced from `4.3sec` to `0.8sec`.
> 
> I decided to keep the sleep time rather a bit higher than strictly required. in most of these cases `100ms` would have been sufficient on my machine already.

Emanuel Peter has updated the pull request incrementally with one additional commit since the last revision:

  copyright updated

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/12514/files
  - new: https://git.openjdk.org/jdk/pull/12514/files/9a904a33..6d76853c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12514&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12514&range=01-02

  Stats: 5 lines in 5 files changed: 2 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/12514.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12514/head:pull/12514

PR: https://git.openjdk.org/jdk/pull/12514