Fix issue with running from adb shell

This fuzzer tries to write a temp file to the CWD. When run on device
from adb shell, it is denied to add a file to /. Specifying the full
path of the temp fixes the issues on device.

Bug: 203902354
Test: locally built and ran on device and host with decent coverage
Change-Id: Ie804f4209e9a38287c5424a5d2613f785d773722
1 file changed