RFR: 8271124: CTW tests crashed with assert(is_valid_method(o)) failed: should be valid jmethodid [v2]

[Coleen Phillimore]

> Add a lock in VirtualSpaceList::contains to protect the virtual space list for Metaspace::contains.  See CR for more details.
> Tested with tier2 linux-aarch64-debug where the failure happened, and tier1-3 linux-x64-debug,linux-x64,windows-x64-debug in progress (almost done but it's being slow today).

Coleen Phillimore has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'master' into jmethodid
 - 8271124: CTW tests crashed with assert(is_valid_method(o)) failed: should be valid jmethodid

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5990/files
  - new: https://git.openjdk.java.net/jdk/pull/5990/files/ea62b5ce..cc2ae480

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5990&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5990&range=00-01

  Stats: 2168 lines in 61 files changed: 1402 ins; 581 del; 185 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5990.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5990/head:pull/5990

PR: https://git.openjdk.java.net/jdk/pull/5990