RFR: JDK-8290067: Show stack dimensions in UL logging when attaching threads

[Thomas Stuefe]

While investigating [JDK-8290059](https://bugs.openjdk.org/browse/JDK-8290059), I found it useful to know the stack dimensions of the attaching thread. That should be added to the "Thread attached" log line.

Before:


[1.051s][info ][os,thread] Thread attached (tid: 167903, pthread id: 140230406712120.


Now:


[1.051s][info ][os,thread] Thread attached (tid: 167903, pthread id: 140230406712120, stack: 0x00007f89ef942a78 - 0x00007f89ef924000 (122k) ).

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Commit messages:
 - add stack dims to UL

Changes: https://git.openjdk.org/jdk/pull/9447/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9447&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290067
  Stats: 16 lines in 4 files changed: 7 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/9447.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9447/head:pull/9447

PR: https://git.openjdk.org/jdk/pull/9447