liblog: use a blocking socket for sending messages to logd

liblog uses a non-blocking socket for sending messages to logd as a
performance/reliability trade-off, favoring not blocking processes
when they log over reliably tracking all logs.

This change asserts that the above is the wrong trade-off: that log
relability is more important than slight delays when logging. Further
points to consider:

1) The new logd implementation without chatty has lower latency and
less variance in its ::Log() function.
2) liblog also writes to /dev/pmsg0 and this call is already blocking.
3) Logging is already expensive and excess spam must be eliminated
regardless.

Bug: 151654749
Bug: 155922578
Bug: 160314220
Test: No messages are dropped by this socket
Change-Id: I163b7d51aa73a10978850f1868cb9fc4bf9ead1b