RFR: 8271931: Make AbortVMOnVMOperationTimeout more resilient to OS scheduling [v5]

[Albert Mingkun Yang]

> Perform VM-op timeout also on the VM thread. If a VM-op is stuck, the existing watcher-thread based machinery will kick in and detect it.
> 
> Test: tier1

Albert Mingkun Yang has updated the pull request incrementally with one additional commit since the last revision:

  remove vmthread assert

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5016/files
  - new: https://git.openjdk.java.net/jdk/pull/5016/files/e9b26426..18de55de

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5016&range=04
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5016&range=03-04

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5016.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5016/head:pull/5016

PR: https://git.openjdk.java.net/jdk/pull/5016