Vim: Dot '.' command with multi-cursor operates multiple times on first line

[mixProtocol]

Using the dot operator (.) to repeat keystrokes in multi-cursor mode results in those keystrokes getting applied multiple times to the line of the first cursor.

To Reproduce

1. Create 3 lines:
   aaa aaaa aaaaa
   bbb bbbb bbbbb
   ccc cccc ccccc

1. Enable multiple cursors at the start of each line.
2. Move to start of second word and prepend '123' with key strokes: w i 123 _esc_
3. Move to start of the third word with keystroke: w
4. Attempt to insert '123' with keystroke: . (period)

Expected behavior
'123' would be prepended to the second word of each line with text now as:
aaa 123aaaa 123aaaaa
bbb 123bbbb 123bbbbb
ccc 123cccc 123ccccc

Actual Results*
aaa 123aaaa 121212333aaaaa
bbb 123bbbb bbbbb
ccc 123cccc ccccc

[ldm0]

.

[gergelyth]

@J-Fields Fixed this in feaf4adb0a98450a2a0a0dfe03556b8f70a9328b (#4778)