RFR: 8296672: Implementation of Virtual Threads (Second Preview) [v2]

[Alan Bateman]

> JEP 436 proposes a second preview of Virtual Threads to allow time for more feedback and to get more experience with this feature. There is no change in direction, no API changes, and no bulk update of the implementation. For the implementation, there has been ~35 changes/issues pushed to the main line, and a few more coming. For this PR, we just bump the JEP number used by javadoc from 425 to 436.

Alan Bateman 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
 - JEP 425 -> JEP 436

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11235/files
  - new: https://git.openjdk.org/jdk/pull/11235/files/4d3460ad..99525fd4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11235&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11235&range=00-01

  Stats: 108818 lines in 1721 files changed: 51177 ins; 38916 del; 18725 mod
  Patch: https://git.openjdk.org/jdk/pull/11235.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11235/head:pull/11235

PR: https://git.openjdk.org/jdk/pull/11235