RFR: 8287901: Loom: Failures with -XX:+VerifyStack

[Ron Pressler]

Please review the following change.

Debugging information added to `frame::describe` (used by `JavaThread::print_frame_layout`) was inaccurate, but proved fatal with `VerifyStack`, which uses the same information for verification.

The location of a caller frame's return address and spilled fp, which are located in the callee, were recorded by the caller frame. In the case of the special frame `Continuation.enterSpecial`, those locations were recorded incorrectly. The fix is to record the information while describing the callee frame, rather than the caller.

Passes tier1

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

Commit messages:
 - 8287901: Loom: Failures with -XX:+VerifyStack

Changes: https://git.openjdk.java.net/jdk/pull/9066/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=9066&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8287901
  Stats: 25 lines in 3 files changed: 11 ins; 2 del; 12 mod
  Patch: https://git.openjdk.java.net/jdk/pull/9066.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/9066/head:pull/9066

PR: https://git.openjdk.java.net/jdk/pull/9066