Update android_device.dart to have clearLogs not print to standard error (flutter#150197)

Even though this does not fix the below issue lets land this anyway as not logging to stderr when clearing logs makes sense to me. 
related flutter#150093 

The test added is bad. It does not verify the behavior changed. 
To verify the behavior changed correctly I would need to modify the generic device class to have clearLogs be an async function like many of the other calls. That would mean modifying every other device type and their implementations and their tests. Then I would need to update android_device to expose its logger. That is more than I have time for to validate a 2% flake error. 

Feel free to disagree in the comments on this pr.

Author: reidbaker

packages/flutter_tools/lib/src/android/android_device.dart

@@ -778,7 +778,12 @@ class AndroidDevice extends Device {
 
   @override
   void clearLogs() {
-    _processUtils.runSync(adbCommandForDevice(<String>['logcat', '-c']));
+     final RunResult result = _processUtils.runSync(adbCommandForDevice(<String>['logcat', '-c']));
+     // Do not log to standard error because that causes test to fail.
+     if (result.exitCode != 0) {
+      _logger.printTrace('"adb logcat -c" failed: exitCode: ${result.exitCode}'
+        ' stdout: ${result.stdout} stderr: ${result.stderr}');
+    }
   }
 
   @override

packages/flutter_tools/test/general.shard/android/android_device_test.dart

@@ -331,6 +331,18 @@ flutter:
     expect(await device.emulatorId, isNull);
   });
 
+  testWithoutContext('AndroidDevice clearLogs does not crash', () async {
+    final AndroidDevice device = setUpAndroidDevice(
+      processManager: FakeProcessManager.list(<FakeCommand>[
+        const FakeCommand(
+          command: <String>['adb', '-s', '1234', 'logcat', '-c'],
+          exitCode: 1,
+        ),
+      ])
+    );
+    device.clearLogs();
+  });
+
   testWithoutContext('AndroidDevice lastLogcatTimestamp returns null if shell command failed', () async {
     final AndroidDevice device = setUpAndroidDevice(
       processManager: FakeProcessManager.list(<FakeCommand>[