RFR: 8301095: [s390x] TestDwarf.java fails [v3]

[Amit Kumar]

> TestDwarf.java fails on s390 due to incorrect returned frame. for dereference_null crash, the (return) pc was selected from gpr14 (in accordance with z-ABI) but correct (return) pc was present at "return_pc" offset. This PR introduces an additional check for the frame type detection. 
> Special Thanks to @RealLucy

Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:

  addressing Lutz comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12306/files
  - new: https://git.openjdk.org/jdk/pull/12306/files/1e828b82..9dd8e10c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12306&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12306&range=01-02

  Stats: 8 lines in 1 file changed: 0 ins; 0 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/12306.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12306/head:pull/12306

PR: https://git.openjdk.org/jdk/pull/12306