Disable verbose serialization of box.error in diff tests

In scope of tarantool/tarantool#9105, we are going to increase the
verbosity of `box.error` serialization. Since the verbose error
representation contains the diagnostic trace, it is unsuitable for diff
tests, so let's disable it from the CLI.

Needed for tarantool/tarantool#9105

lib/server.py

@@ -35,6 +35,13 @@ class Server(object):
         assert(box.error.injection.set('ERRINJ_AUTO_UPGRADE', true) == 'ok', \
         'no such errinj')"
 
+    # Since the verbose box.error representation contains the diagnostic trace,
+    # it is unsuitable for diff tests, and we disable it from the CLI.
+    DISABLE_BOX_ERROR_SERIALIZE_VERBOSE = \
+        "if require('internal.tweaks').box_error_serialize_verbose ~= nil " \
+        "then require('internal.tweaks').box_error_serialize_verbose = false " \
+        "end"
+
     @property
     def vardir(self):
         if not hasattr(self, '_vardir'):

lib/tarantool_server.py

@@ -839,11 +839,12 @@ def copy_files(self):
             shutil.copy(self.snapshot_path, snapshot_dest)
 
     def prepare_args(self, args=[]):
-        cli_args = [self.ctl_path, 'start',
+        cli_args = [self.binary, '-e', self.DISABLE_BOX_ERROR_SERIALIZE_VERBOSE,
+                    self.ctl_path, 'start',
                     os.path.basename(self.script)] + args
         if self.disable_schema_upgrade:
-            cli_args = [self.binary, '-e',
-                        self.DISABLE_AUTO_UPGRADE] + cli_args
+            cli_args = cli_args[0] + ['-e', self.DISABLE_AUTO_UPGRADE] + \
+                       cli_args[1:]
 
         return cli_args