headless: Don't run tests during the build

headless/BUILD.gn

Index: headless/BUILD.gn
diff --git a/headless/BUILD.gn b/headless/BUILD.gn
index 8e5970bde4a3b4b3a500f2adb226b79b443d53a2..7bb59619e20418cd2da1fcf95224d496fa6cfff2 100644
--- a/headless/BUILD.gn
+++ b/headless/BUILD.gn
@@ -255,7 +255,6 @@ group("headless_tests") {
   testonly = true
 
   deps = [
-    ":client_api_generator_tests",
     ":headless_browsertests",
     ":headless_unittests",
   ]
@@ -281,23 +280,6 @@ test("headless_unittests") {
   ]
 }
 
-action("client_api_generator_tests") {
-  _stamp = "$target_gen_dir/client_api_generator_unittests.stamp"
-  inputs = [
-    "lib/browser/client_api_generator.py",
-    "lib/browser/client_api_generator_unittest.py",
-  ]
-  outputs = [
-    _stamp,
-  ]
-
-  script = "lib/browser/client_api_generator_unittest.py"
-  args = [
-    "--stamp",
-    rebase_path(_stamp, root_build_dir),
-  ]
-}
-
 mojom("embedder_mojo_for_testing") {
   sources = [
     "lib/embedder_test.mojom",