fix: only kill the process when there is no browser instance available (#7762)

When the browser has been started and we have a valid reference lets make use of it instead of force-killing the process. A force kill should probably be the last resort in cleaning up the process.

This will help with Firefox as described on #7668 (comment).

Author: whimboo

src/node/Launcher.ts

@@ -174,28 +174,37 @@ class ChromeLauncher implements ProductLauncher {
       pipe: usePipe,
     });
 
+    let browser;
     try {
       const connection = await runner.setupConnection({
         usePipe,
         timeout,
         slowMo,
         preferredRevision: this._preferredRevision,
       });
-      const browser = await Browser.create(
+      browser = await Browser.create(
         connection,
         [],
         ignoreHTTPSErrors,
         defaultViewport,
         runner.proc,
         runner.close.bind(runner)
       );
-      if (waitForInitialPage)
-        await browser.waitForTarget((t) => t.type() === 'page', { timeout });
-      return browser;
     } catch (error) {
       runner.kill();
       throw error;
     }
+
+    if (waitForInitialPage) {
+      try {
+        await browser.waitForTarget((t) => t.type() === 'page', { timeout });
+      } catch (error) {
+        await browser.close();
+        throw error;
+      }
+    }
+
+    return browser;
   }
 
   defaultArgs(options: BrowserLaunchArgumentOptions = {}): string[] {
@@ -371,28 +380,37 @@ class FirefoxLauncher implements ProductLauncher {
       pipe,
     });
 
+    let browser;
     try {
       const connection = await runner.setupConnection({
         usePipe: pipe,
         timeout,
         slowMo,
         preferredRevision: this._preferredRevision,
       });
-      const browser = await Browser.create(
+      browser = await Browser.create(
         connection,
         [],
         ignoreHTTPSErrors,
         defaultViewport,
         runner.proc,
         runner.close.bind(runner)
       );
-      if (waitForInitialPage)
-        await browser.waitForTarget((t) => t.type() === 'page', { timeout });
-      return browser;
     } catch (error) {
       runner.kill();
       throw error;
     }
+
+    if (waitForInitialPage) {
+      try {
+        await browser.waitForTarget((t) => t.type() === 'page', { timeout });
+      } catch (error) {
+        await browser.close();
+        throw error;
+      }
+    }
+
+    return browser;
   }
 
   executablePath(): string {