Fix thread correctness issue in OldAndroidMonitorTest.

The waiter thread was looping on a non-volatile variable and
therefore not guaranteed to observe any reads or writes to that
variable.

Signed-off-by: Junjie Hu <junjie.hu@mediatek.com>

Change-Id: I6e52e456636774c492690179b9d84a250aec2637
Merge "Fix thread correctness issue in OldAndroidMonitorTest."