Fixing deadlock in OomAdjProfiler.

During dumping, the ActivityManager lock is held. If a CPU time update
was scheduled before a dump but the background thread was working on a
task that required the ActivityManager lock, OomAdjProfiler would wait
indefinitely for the update in the dump() method because the AM lock is
already taken in the main thread. Removing the wait and updating the CPU
time in the main thread during dumping only should avoid the potential
deadlock.

Bug: 130635979
Test: adb shell dumpsys activity
Change-Id: Ibafe79b46babe16f589ec28d525174f9a01f00b8