Fix Typos (flutter#137173)

Fix Small Typos.

Author: piedcipher

packages/flutter/test/material/action_icons_theme_test.dart

@@ -37,7 +37,7 @@ void main() {
     expect(copy.drawerButtonIconBuilder, originalButtonBuilder);
     expect(copy.endDrawerButtonIconBuilder, originalButtonBuilder);
 
-    // Check if the properties are overriden.
+    // Check if the properties are overridden.
     final ActionIconThemeData overridden = original.copyWith(
       backButtonIconBuilder: newButtonBuilder,
       closeButtonIconBuilder: newButtonBuilder,

packages/flutter_test/lib/src/finders.dart

@@ -965,7 +965,7 @@ mixin _LegacyFinderMixin on FinderBase<Element> {
 /// A base class for creating finders that search the [Element] tree for
 /// [Widget]s.
 ///
-/// The [findInCandidates] method must be overriden and will be enforced at
+/// The [findInCandidates] method must be overridden and will be enforced at
 /// compilation after [apply] is removed.
 abstract class Finder extends FinderBase<Element> with _LegacyFinderMixin {
   /// Creates a new [Finder] with the given `skipOffstage` value.