RFR: 8264372: Threads::destroy_vm only ever returns true [v2]

[David Holmes]

> Trivial cleanup to remove the bool return from Threads::destroy_vm as it only ever returned true.
> 
> Testing: tiers 1-3
> 
> Thanks,
> David

David Holmes has updated the pull request incrementally with one additional commit since the last revision:

  Adjusted comment

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3535/files
  - new: https://git.openjdk.java.net/jdk/pull/3535/files/778b233b..371c2d15

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3535&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3535&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3535.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3535/head:pull/3535

PR: https://git.openjdk.java.net/jdk/pull/3535