Fix descriptor leak after accepting connections

After accepting a connection on a listening socket and
storing the resulting FileDescriptor into a newly created
LocalSocketImpl, the new impl's "descriptor was created
locally and should be closed normally" flag should be set.

(cherrypicked from 3e7305c6)

Bug: 11805817
Change-Id: I0a1a7c62ec3fbcf647a44a22110ddc778d14e5f4