RFR: 8302158: PPC: test/jdk/jdk/internal/vm/Continuation/Fuzz.java: AssertionError: res: false shouldPin: false [v2]

[Richard Reingruber]

> This fixes the linked issue by trimming the caller of a frame to be deoptimized back to its `unextended_sp` iff it is compiled. The creation of the section `dead after deoptimization` shown in the attachment [yield_after_deopt_failure.log](https://bugs.openjdk.org/secure/attachment/102602/yield_after_deopt_failure.log) is prevented by this.
> 
> A new mode is added to the test BasicExt.java where all frames are deoptimized after a yield operation. The issue can be deterministically reproduced with the new mode. It's not worth to execute all test cases with the new mode though. Instead `ContinuationCompiledFramesWithStackArgs_3c4` is always executed a 2nd time in this mode.
> 
> Before this BasicExt.java was refactored for better argument processing and representation of the test modes.
> Also the try-catch-clause in the main method had to be changed to rethrow the caught exception because without this the test would have succeeded.
> 
> Testing: jtreg tests tier 1-4 on standard platforms and also on ppc64le.

Richard Reingruber has updated the pull request incrementally with three additional commits since the last revision:

 - Improve comment
 - Improve comment
 - Spelling

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/12557/files
  - new: https://git.openjdk.org/jdk/pull/12557/files/7ca17977..9d647388

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12557&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12557&range=00-01

  Stats: 5 lines in 2 files changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/12557.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12557/head:pull/12557

PR: https://git.openjdk.org/jdk/pull/12557