RFR: 8370240: [PPC64] jhsdb jstack cannot handle continuation stub [v2]

[David Briemann]

> This is a port of 8369979 for PPC. It allows to calculate caller SP from `CodeBlob` for continuation stub.
> It also enables the test `test/hotspot/jtreg/serviceability/sa/TestJhsdbJstackWithVirtualThread.java` for PPC.

David Briemann has updated the pull request incrementally with one additional commit since the last revision:

  remove unnecessary requires

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27902/files
  - new: https://git.openjdk.org/jdk/pull/27902/files/3aedfd5c..056a8b59

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27902&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27902&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/27902.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27902/head:pull/27902

PR: https://git.openjdk.org/jdk/pull/27902