Corrected buffer overflow when parsing /proc/wakelocks

The android_os_Process_parseProcLineArray in android_util_Process.cpp
writes up to buffer[endIndex]. This sometimes caused an assert to be
triggered in NewStringUTF when the output from /proc/wakelocks was
larger than 4096 bytes. The buffer was also increased in order to be
able to parse all wakelocks completely.

Change-Id: Idf8e66d61ad979377569048f59c3eee278b146db