Support --local-engine=ios_debug_sim (#119524)

Fixes:

* https://github.com/flutter/flutter/issues/119523

packages/flutter_tools/lib/src/runner/local_engine.dart

@@ -157,7 +157,7 @@ class LocalEngineLocator {
   }
 
   // Determine the host engine directory associated with the local engine:
-  // Strip '_sim_' since there are no host simulator builds.
+  // Strip '_sim' since there are no host simulator builds.
   String _getHostEngineBasename(String localEngineBasename) {
     if (localEngineBasename.startsWith('web_') ||
         localEngineBasename.startsWith('wasm_') ||
@@ -166,7 +166,7 @@ class LocalEngineLocator {
       return localEngineBasename;
     }
 
-    String tmpBasename = localEngineBasename.replaceFirst('_sim_', '_');
+    String tmpBasename = localEngineBasename.replaceFirst('_sim', '');
     tmpBasename = tmpBasename.substring(tmpBasename.indexOf('_') + 1);
     // Strip suffix for various archs.
     const List<String> suffixes = <String>['_arm', '_arm64', '_x86', '_x64'];

packages/flutter_tools/test/general.shard/runner/local_engine_test.dart

@@ -170,6 +170,61 @@ void main() {
     );
   });
 
+  testWithoutContext('works if local engine is simulator', () async {
+    final FileSystem fileSystem = MemoryFileSystem.test();
+    final Directory localEngine = fileSystem
+        .directory('$kArbitraryEngineRoot/src/out/ios_debug_sim/')
+      ..createSync(recursive: true);
+    fileSystem
+        .directory('$kArbitraryEngineRoot/src/out/host_debug/')
+        .createSync(recursive: true);
+
+    final BufferLogger logger = BufferLogger.test();
+    final LocalEngineLocator localEngineLocator = LocalEngineLocator(
+      fileSystem: fileSystem,
+      flutterRoot: 'flutter/flutter',
+      logger: logger,
+      userMessages: UserMessages(),
+      platform: FakePlatform(environment: <String, String>{}),
+    );
+
+    expect(
+      await localEngineLocator.findEnginePath(localEngine: localEngine.path),
+      matchesEngineBuildPaths(
+        hostEngine: '/arbitrary/engine/src/out/host_debug',
+        targetEngine: '/arbitrary/engine/src/out/ios_debug_sim',
+      ),
+    );
+  });
+
+  testWithoutContext('works if local engine is simulator unoptimized',
+      () async {
+    final FileSystem fileSystem = MemoryFileSystem.test();
+    final Directory localEngine = fileSystem
+        .directory('$kArbitraryEngineRoot/src/out/ios_debug_sim_unopt/')
+      ..createSync(recursive: true);
+    fileSystem
+        .directory('$kArbitraryEngineRoot/src/out/host_debug_unopt/')
+        .createSync(recursive: true);
+
+    final BufferLogger logger = BufferLogger.test();
+    final LocalEngineLocator localEngineLocator = LocalEngineLocator(
+      fileSystem: fileSystem,
+      flutterRoot: 'flutter/flutter',
+      logger: logger,
+      userMessages: UserMessages(),
+      platform: FakePlatform(environment: <String, String>{}),
+    );
+
+    expect(
+      await localEngineLocator.findEnginePath(localEngine: localEngine.path),
+      matchesEngineBuildPaths(
+        hostEngine: '/arbitrary/engine/src/out/host_debug_unopt',
+        targetEngine: '/arbitrary/engine/src/out/ios_debug_sim_unopt',
+      ),
+    );
+  });
+
   testWithoutContext('fails if host_debug does not exist', () async {
     final FileSystem fileSystem = MemoryFileSystem.test();
     final Directory localEngine = fileSystem