The cursor often is stuck at the beginning of the TextField when typing strings of emojis (as well as some other types of characters)

Repro:

• Open any flutter TextField (the one in flutter_gallery>material>text fields should do)
• Type emoji characters, preferably ones with zero-width-joiners such as nation flags
• Cursor is stuck at front, and tapping in the text works (new text shows up correctly, backspacing works) but the cursor does not appear in the right spot.

This sometimes goes away when there are other characters around the emoji string.