test: improved stability of tst_qwaitcondition

test: improved stability of tst_qwaitcondition

Increased thread wait timeout from 3 to 10 milliseconds, for slower or
heavily loaded machines.  (There was a previous attempt to improve
stability of this test some time ago by increasing the timeout from 1
to 3 milliseconds.)

Note that this increases the runtime of the wakeOne test from ~5 to ~14
seconds.

Change-Id: Ib556d4c949a6989fe71c11f5dc10feb2ec45c512
Reviewed-on: http://codereview.qt.nokia.com/2458
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Kalle Lehtonen <kalle.ju.lehtonen@nokia.com>