fix(android): Normalize start and end args (#24938)

Summary:
Fixes #18579

Normalize `start` and `end` arguments when `onSelectionChange` is
dispatched on Android.

It just applies a [fix](https://github.com/facebook/react-native/issues/18579#issuecomment-474466525) sent by TheSavior (Thanks, by the way 😄)

## Changelog

[Android] [Fixed] - fix(android): Normalize start and end args
Pull Request resolved: https://github.com/facebook/react-native/pull/24938

Differential Revision: D15412005

Pulled By: cpojer

fbshipit-source-id: bb132313cfb8877a682f3865a5f9e48d45ac20ac

ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactTextInputManager.java

@@ -963,16 +963,22 @@ public class ReactTextInputManager extends BaseViewManager<ReactEditText, Layout
       // Android will call us back for both the SELECTION_START span and SELECTION_END span in text
       // To prevent double calling back into js we cache the result of the previous call and only
       // forward it on if we have new values
-      if (mPreviousSelectionStart != start || mPreviousSelectionEnd != end) {
+
+      // Apparently Android might call this with an end value that is less than the start value
+      // Lets normalize them. See https://github.com/facebook/react-native/issues/18579
+      int realStart = Math.min(start, end);
+      int realEnd = Math.max(start, end);
+
+      if (mPreviousSelectionStart != realStart || mPreviousSelectionEnd != realEnd) {
         mEventDispatcher.dispatchEvent(
             new ReactTextInputSelectionEvent(
                 mReactEditText.getId(),
-                start,
-                end
+                realStart,
+                realEnd
             ));
 
-        mPreviousSelectionStart = start;
-        mPreviousSelectionEnd = end;
+        mPreviousSelectionStart = realStart;
+        mPreviousSelectionEnd = realEnd;
       }
     }
   }