IndexOutOfBoundsException observed rarely in ProcessStats

Sometime IndexOutOfBoundsException is observed in ProcessStats
while allocating longs array. This could be due to synchronization.
This fix will return if array index is >= size.

Change-Id: I1df34152c95f2ff61829da07f750e79a6f1efab3
CRs-fixed: 626638
Signed-off-by: houst0nn <houstonn@gmail.com>