Bug 1492700 - Fix ADB stop() in case ADB start() was called several times;r=daisuke

Differential Revision: https://phabricator.services.mozilla.com/D12758

--HG--
extra : moz-landing-system : lando

devtools/shared/adb/adb.js

@@ -89,7 +89,6 @@ const ADB = {
 
       const isAdbRunning = await check();
       if (isAdbRunning) {
-        this.didRunInitially = false;
         dumpn("Found ADB process running, not restarting");
         onSuccessfulStart();
         return;

devtools/shared/adb/test/test_adb.js

@@ -175,13 +175,24 @@ add_task({
 
   await extension.startup();
 
+  // Call start() once and call stop() afterwards.
   await ADB.start();
   ok(ADB.ready);
-
   ok(await check(), "adb is now running");
 
   await ADB.stop();
   ok(!ADB.ready);
+  ok(!(await check()), "adb is no longer running");
+
+  // Call start() twice and call stop() afterwards.
+  await ADB.start();
+  await ADB.start();
+  ok(ADB.ready);
+  ok(await check(), "adb is now running");
+
+  await ADB.stop();
+  ok(!ADB.ready);
+  ok(!(await check()), "adb is no longer running");
 
   await extension.unload();
 });