Log instances where ParcelFileDescriptor.open is called with mode

w, but without a or t. Starting in Android Q, the ParcelFileDescriptor#parseMode method no longer implicitly adds the truncate flag to mode "w". This commit adds logging to the central location where the result of parseMode would typically be passed to identify apps potentially affected by this change.
Test: manual test.

Change-Id: I35e0ceaafff0bef616ce8f998530cc610206e46b