adb: actually enable fdsan.

adb was using a custom unique_fd closer that didn't have an
implementation for fdsan, which meant that none of our FDs were
actually tracked. Guard this behind ifdefs so that we only use this
on Windows, and delete our implementation of Pipe in favor of the one
in libbase while we're at it. libbase's implementation always sets
O_CLOEXEC, so fix up the instance of Pipe that doesn't expect that.

Test: mma
Test: adb start-server
Test: debuggerd `pidof adbd`
Change-Id: Ic29d641a2f93fb42384b00c51775048c8bcbe152