Multiple tests are batch-compiled into 1 replay application instead of
multiple replay applications. Replay application now runs generated
code of multiple tests instead of 1 test. This reduces overhead cost
and brings down runtime.

Main process now receives messages sent by workers via a message queue
and prints them to the main stdout so that user can know if workers are
hanging.

Add handle for user interrupt (Ctrl-C) so that processes are properly
destroyed and cleaned up.

Trace files now have the option not to be deleted.

Bug: angleproject:4817
Change-Id: Ic90ae0f430e1d3c261ffea5f963be5a4e94b0ad2
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2310909Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Manh Nguyen <nguyenmh@google.com>