Rename native_driver to android_{driver_extensions|engine_test} (#161263)

Towards https://github.com/flutter/flutter/issues/161261 (before I add
more tests).

This is a 1:1 move, with massaging of
`run_flutter_driver_android_tests.dart` to be more automated as tests
are added.

/cc @reidbaker

dev/tools/android_driver_extensions/README.md

@@ -1,14 +1,14 @@
-# Flutter Native Driver
+# Android Extensions for Flutter Driver
 
 This a minimal library on top of `flutter_driver` that provides extensions for
-interacting with the native platform, to otherwise perform actions that are not
-possible purely through Flutter Driver, and would want to run as an _external_
-test (run on the host, not on the device):
+interacting with the native Android platform, to otherwise perform actions that
+are not possible purely through Flutter Driver, and would want to run as an
+_external_ test (run on the host, not on the device):
 
 - Take a screenshot, including of _native_ widgets (platform views, textures)
 - Tap on a native widget
 - Rotate the device
-- (Android Only) Background an app and send a "trim memory" signal to the device
+- Background an app and send a "trim memory" signal to the device
 
 > [!NOTE]
 >

dev/tools/android_driver_extensions/pubspec.yaml

@@ -1,4 +1,4 @@
-name: native_driver
+name: android_driver_extensions
 
 environment:
   sdk: ^3.7.0-0

dev/tools/android_driver_extensions/test/adb_fake_io_test.dart

@@ -4,7 +4,7 @@
 
 import 'dart:typed_data';
 
-import 'package:native_driver/src/backend/android/adb.dart';
+import 'package:android_driver_extensions/src/backend/android/adb.dart';
 import 'package:process/process.dart';
 import 'package:test/test.dart';
 

dev/tools/android_driver_extensions/test/android_driver_fake_test.dart

@@ -5,7 +5,7 @@
 import 'dart:io' as io;
 import 'dart:typed_data';
 
-import 'package:native_driver/native_driver.dart';
+import 'package:android_driver_extensions/native_driver.dart';
 import 'package:test/test.dart';
 
 import 'src/fake_adb.dart';

dev/tools/android_driver_extensions/test/src/fake_adb.dart

@@ -4,7 +4,7 @@
 
 import 'dart:typed_data';
 
-import 'package:native_driver/src/backend/android.dart';
+import 'package:android_driver_extensions/src/backend/android.dart';
 
 /// A stub of [Adb] that allows overriding its methods.
 ///