fix potential memory leak

use fclose() before return.

Change-Id: I3ed193464cc0dc90e9935ae19162667ad367628b
frameworks/base: Increase Zygote preload GC threshold to half the heapgrowthlimit.

Increase Zygote preload GC threshold to half the heapgrowthlimit,
to reduce boot up time.

ps2: add missing include

Change-Id: I6ea0f115e5f96836adec5ba9b796f54e6e898643