Fix memory leak in SuspendBlockerImpl

The cl removes the mOpenReferenceTimes entries
for the cls without active acquisitions.

The cl also preallocates the LongArray containing the acquisition
times to 2 elements, since based on the heapdump is looks underutilized
and default initial allocation of 12 seems too big.

Bug: 290346048
Test: atest PowerManagerServiceTest
Test: verified system server heapdump

Change-Id: Ic2f810e1ffe99a7ed8c36fd0e0ac44446dc65b67