[flutter_tools] only apply --strip to iOS gen_snapshot in release mode (#49596)

packages/flutter_tools/lib/src/base/build.dart

@@ -139,7 +139,7 @@ class AOTSnapshotter {
       genSnapshotArgs.add('--assembly=$assembly');
       // TODO(jonahwilliams): determine the correct time to use strip
       // since this is required for the future dwarf strack traces option.
-      if (bitcode) {
+      if (bitcode && buildMode == BuildMode.release) {
         genSnapshotArgs.add('--strip');
       }
     } else {

packages/flutter_tools/test/general.shard/base/build_test.dart

@@ -326,7 +326,6 @@ void main() {
         '--deterministic',
         '--snapshot_kind=app-aot-assembly',
         '--assembly=$assembly',
-         '--strip',
         '--no-sim-use-hardfp',
         '--no-use-integer-division',
         '--no-causal-async-stacks',