Add CTS telemetry harness support

Migrates harness support files added in
https://chromium-review.googlesource.com/c/chromium/src/+/3541414
into Dawn's repo.

Tested in
https://chromium-review.googlesource.com/c/chromium/src/+/3537743

Bug: chromium:1306640
Change-Id: I3000b1223219a1da293af910bf442570b70b7c92
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/84043
Reviewed-by: Loko Kung <lokokung@google.com>
Commit-Queue: Austin Eng <enga@chromium.org>

webgpu-cts/scripts/tsc_ignore_errors.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python
+#
+# Copyright 2022 The Dawn Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import subprocess
+import sys
+import os
+
+from dir_paths import node_dir
+
+try:
+    old_sys_path = sys.path
+    sys.path = [node_dir] + sys.path
+
+    from node import GetBinaryPath as get_node_binary_path
+finally:
+    sys.path = old_sys_path
+
+tsc = os.path.join(node_dir, 'node_modules', 'typescript', 'lib', 'tsc.js')
+
+
+def run_tsc_ignore_errors(args):
+    cmd = [get_node_binary_path(), tsc] + args
+    process = subprocess.Popen(cmd,
+                               cwd=os.getcwd(),
+                               stdout=subprocess.PIPE,
+                               stderr=subprocess.PIPE)
+
+    stdout, stderr = process.communicate()
+
+    # Typecheck errors go in stdout, not stderr. If we see something in stderr, raise an error.
+    if len(stderr):
+        raise RuntimeError('tsc \'%s\' failed\n%s' % (' '.join(cmd), stderr))
+
+    return stdout
+
+
+if __name__ == '__main__':
+    run_tsc_ignore_errors(sys.argv[1:])