Move *_test_runner to legacy_test_runner

All layout tests are using `loadTestModule` and therefore, we can
now move all folders containing legacy layout test runners into
`legacy_test_runner`. Moreover, we can now remove the `module.json`
files in all of these folders.

We now include integration_test_runner as an entrypoint. As such,
build_release_applications no longer processes integration_test_runner
and GN takes over.

[email protected]

Bug: 1187573, 1127902
Change-Id: I6b93bdf8fccc99dbfd4c9ce8cd55e03f55f6b1bd
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2784729
Commit-Queue: Tim van der Lippe <[email protected]>
Reviewed-by: Paul Lewis <[email protected]>
diff --git a/front_end/integration_test_runner.html b/front_end/integration_test_runner.html
index 971f15e..482deda 100644
--- a/front_end/integration_test_runner.html
+++ b/front_end/integration_test_runner.html
@@ -8,7 +8,7 @@
 <head>
     <meta charset="utf-8">
     <!-- <meta http-equiv="Content-Security-Policy" content="object-src 'none'; script-src 'self' 'unsafe-eval' 'unsafe-inline' https://chrome-devtools-frontend.appspot.com"> -->
-    <script type="module" src="integration_test_runner.js"></script>
+    <script type="module" src="legacy_test_runner/legacy_test_runner.js"></script>
 </head>
 <body id="-blink-dev-tools"></body>
 </html>