runhat: use /data/local/tmp

Use /data/local/tmp for runhat reports, instead of the sdcard.
system_server isn't allowed to handle sdcard file descriptors, since
the sdcard could be ejected at any time, causing the kernel to kill the
system process.

This addresses the following SELinux denial:

  W/main    ( 9906): type=1400 audit(0.0:16): avc: denied { read write } for path="/mnt/shell/emulated/0/hprof-600" dev="fuse" ino=3077890536 scontext=u:r:system_server:s0 tcontext=u:object_r:fuse:s0 tclass=file

Bug: 16375996
Change-Id: I4c2053c327526c2f8e6812f4ed911a712ae9a9b8