adb: make sure that file mode macros match linux.

We use <sys/stat.h> mode macros on the host to parse modes sent over
from the device, so they had better match. Add static_asserts to ensure
this.

(Also, fix the cases where they don't.)

Test: mma -j48, compiled the static_asserts on darwin manually
Change-Id: I883e4e6c7489ea64d3c02d26790ac8293366d989