Use SOCK_CLOEXEC when possible.
Use SOCK_CLOEXEC when possible.

This removes the window during which fork / exec end up leaking the socket.
This can happen for heapprofd client.

Change-Id: Iaf0da6c8e9b2f060f5b887053e5a9b82323d9f65
google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto