This adds a new `--debug-exit-on-error` flag. When it is set, Blender
will abort with a non-zero exit code when there are internal errors.
Currently, "internal errors" includes memory leaks detected by
guardedalloc and error/fatal log entries in clog.
The new flag is passed to Blender in various places where automated
tests are run. Furthermore, the `--debug-memory` flag is used in tests,
because that makes the verbose output more useful, when dealing
with memory leaks.
Reviewers: brecht, sergey
Differential Revision: https://developer.blender.org/D8665
8a9912eaf8