Allow running JitHarness (and other unittests) on Android

Steps:

1. `cd android`
2. `ab -DUNITTEST=1 APP_ABI=armeabi-v7a` (APP_ABI is just to build faster... can also add ` NDK_DEBUG=1` for gdb/ds-5 and ` HEADLESS=1`)
3. `adb push libs/armeabi-v7a/ppsspp_unittest //data/local/tmp/`
4. `adb shell "chmod 0777 /data/local/tmp/ppsspp_unittest"`
5. `adb shell /data/local/tmp/ppsspp_unittest Jit"`

-[Unknown]