RFR: 8286446: PPC64: fix crashes after JDK-8284161 (virtual threads preview)

[Richard Reingruber]

With this change `java -version` succeeds with the devkit build also the standard build on a ppc64le box does not crash anymore.

Also tier1 tests don't look too bad.

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Commit messages:
 - frame::patch_pc
 - frame::get_oop_map
 - Initialize new frame members
 - Fix Continuation::is_cont_barrier_frame
 - Fix ppc StubGenerator
 - TemplateInterpreterGenerator::generate_Continuation_doYield_entry
 - Fingerprinter::do_type_calling_convention
 - NativeDeoptInstruction::is_deopt_at

Changes: https://git.openjdk.java.net/jdk/pull/8617/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8617&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8286446
  Stats: 225 lines in 8 files changed: 177 ins; 10 del; 38 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8617.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8617/head:pull/8617

PR: https://git.openjdk.java.net/jdk/pull/8617