Add test-suite-source-dir flag to new test runner

The current tests try to figure out the root directory and then glob
for _test.ts files within there, but this breaks easily if the folder
structure isn't exactly as expected. Instead we can set this via a
flag in the test runner.

This CL only updates the interaction tests, which use the new runner.
e2e tests will be supported in time.

Bug: chromium:1186163
Change-Id: I198b67bf0081ce7334c40d7d661fb8642c2d56d0
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2772045
Commit-Queue: Jack Franklin <jacktfranklin@chromium.org>
Auto-Submit: Jack Franklin <jacktfranklin@chromium.org>
Reviewed-by: Paul Lewis <aerotwist@chromium.org>
diff --git a/scripts/component_server/server.js b/scripts/component_server/server.js
index 358179d..bcbaad8 100644
--- a/scripts/component_server/server.js
+++ b/scripts/component_server/server.js
@@ -7,19 +7,8 @@
 const path = require('path');
 const parseURL = require('url').parse;
 const {argv} = require('yargs');
+const {getTestRunnerConfigSetting} = require('../test/test_config_helpers.js');
 
-function getTestRunnerConfig() {
-  try {
-    return JSON.parse(process.env.TEST_RUNNER_JSON_CONFIG);
-  } catch {
-    // Return an empty object so any lookups return undefined
-    return {};
-  }
-}
-function getTestRunnerConfigSetting(settingKey, fallbackValue) {
-  const config = getTestRunnerConfig();
-  return config[settingKey] === undefined ? fallbackValue : config[settingKey];
-}
 
 const serverPort = parseInt(process.env.PORT, 10) || 8090;
 const target = argv.target || process.env.TARGET || 'Default';