gn_check_autofix: increase error limit for gn check

which after usage of -r to remove all target as of recently runs into
  Too many errors/warnings. Suppressing further messages.
  You can change the limit by passing --error-limit=<number>.
which leads to not fixing errors. Passing a sufficiently high number
as error limit avoids that.

Doing
  tools_webrtc/gn_check_autofix.py -r api/BUILD.gn
followed by
  tools_webrtc/gn_check_autofix -C out/Default
should again require no(t much) more than a single pass.

Bug: webrtc:467294026
Change-Id: I4912bdc6555256f7fbb55a0768296f0ab72f21a9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/458520
Commit-Queue: Philipp Hancke <philipp.hancke@googlemail.com>
Reviewed-by: Jeremy Leconte <jleconte@google.com>
Reviewed-by: Christoffer Dewerin <jansson@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47214}

tools_webrtc/gn_check_autofix.py

@@ -272,7 +272,14 @@ useful to check for different configurations."""
     errors_by_file = defaultdict(lambda: defaultdict(set))
 
     if flags.local_build_dir:
-        mb_output = Run(["gn", "gen", "--check", flags.local_build_dir])
+        mb_output = Run([
+            "gn",
+            "gen",
+            "--check",
+            # High limit to expose all errors to the tool.
+            "--error-limit=20000",
+            flags.local_build_dir
+        ])
     else:
         with TemporaryDirectory() as tmp_dir:
             mb_script_path = os.path.join(SCRIPT_DIR, 'mb', 'mb.py')