RFR: 8282477: [x86, aarch64] vmassert(_last_Java_pc == NULL, "already walkable"); fails with async profiler [v3]

[Johannes Bechberger]

> Fix the assertion by replacing it by assertion that does not fail.

Johannes Bechberger has updated the pull request incrementally with one additional commit since the last revision:

  Use make_walkable

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8209/files
  - new: https://git.openjdk.java.net/jdk/pull/8209/files/f152367b..83ed9c70

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8209&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8209&range=01-02

  Stats: 76 lines in 7 files changed: 1 ins; 55 del; 20 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8209.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8209/head:pull/8209

PR: https://git.openjdk.java.net/jdk/pull/8209