Avoid use of pthread_getschedparam

During Thread::DumpState the pthread may have exited.
We have the tid, use that instead.

Test: m -j50 test-art-host -k
Test: adb shell kill -3 `pid system_server`
Bug: 36445592
Change-Id: Idb28fcb1f9232768d32966973fe9dbeb3fa74b56
1 file changed