libbinder: remove overeager fdsan crash

In the continueWrite case, if a Parcel contians FDs,
we try to tag the FDs we own in Parcel a second time.
This causes a crash.

Bug: 384097481
Test: with fuzzer, on device and host
Ignore-AOSP-First: fuzzing
Change-Id: I01b2312c316fa457781a4a0c1a81bfd845d0e60e