Fixed compile error in AOSP due to use of guava 23 API.

Futures.submitAsync is V23 and AOSP is currently stuck at V20.

This is just a completely non-sensical dummy implementation of DialerFutureSerializer until we can figure out what to do.

Test: tap
PiperOrigin-RevId: 178323108
Change-Id: I1dc2c8ddfa7ef3e15170543dadefbe4fc2e19226
1 file changed