RFR: 8282477: [x86, aarch64] vmassert(_last_Java_pc == NULL, "already walkable"); fails with async profiler [v4]

[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:

  Remove Thread from make_walkable signature

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8209/files
  - new: https://git.openjdk.java.net/jdk/pull/8209/files/83ed9c70..c6b6b6d6

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8209&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8209&range=02-03

  Stats: 26 lines in 17 files changed: 3 ins; 2 del; 21 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