Bug 1475071 - Enable --no-sync and --debug-logging when running tup; r=chmanchester

The --no-sync flag turns off the SQLite synchronous pragma, so we don't
force the disk to sync on every 'mach build'. Since mach always touches
a few files (eg: warnings.json, .purgecaches, etc), there is always a
minor amount of updates to the database, and syncing them every time
just forces an unnecessary delay.

The --debug-logging flag saves logs under .tup/log to show what files
changes or were deleted, as well as the corresponding build DAG. This
can be helpful when trying to investigate why something was rebuilt.

MozReview-Commit-ID: L0m7IsYlFUI

--HG--
extra : rebase_source : 0a26bf49778dfa13644f200be3e7061491b135c0

python/mozbuild/mozbuild/backend/tup.py

@@ -291,6 +291,8 @@ class TupBackend(CommonBackend):
         args = [self.environment.substs['TUP'], 'upd'] + what
         if self.environment.substs.get('MOZ_AUTOMATION'):
             args += ['--quiet']
+        else:
+            args += ['--debug-logging']
         if verbose:
             args += ['--verbose']
         if jobs > 0:
@@ -671,7 +673,7 @@ class TupBackend(CommonBackend):
         # Run 'tup init' if necessary.
         if not os.path.exists(mozpath.join(self.environment.topsrcdir, ".tup")):
             tup = self.environment.substs.get('TUP', 'tup')
-            self._cmd.run_process(cwd=self.environment.topsrcdir, log_name='tup', args=[tup, 'init'])
+            self._cmd.run_process(cwd=self.environment.topsrcdir, log_name='tup', args=[tup, 'init', '--no-sync'])
 
 
     def _get_cargo_flags(self, obj):