RFR: Don't assert for getting the name of thread->threadObj() if debugging.

[Coleen Phillimore]

I keep hitting this assert using ps() from the debugger.  This builds without any error.

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

Commit messages:
 - Don't assert for getting the name of thread->threadObj() if debugging.

Changes: https://git.openjdk.java.net/loom/pull/181/files
 Webrev: https://webrevs.openjdk.java.net/?repo=loom&pr=181&range=00
  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/loom/pull/181.diff
  Fetch: git fetch https://git.openjdk.java.net/loom pull/181/head:pull/181

PR: https://git.openjdk.java.net/loom/pull/181