The --watch option should clear the screen scrollback buffer as well as
the screen itself.
On Ubuntu (22.04 Jammy) the 'clear' command generates
"\x1B[H\x1B[2J\x1B[3J"; that is:
- \E[H - cursor home
- \E[2J - clear entire screen
- \E[3J - clear entire screen & scrollback buffer.
By contrast, Deno defined CLEAR_SCREEN as "\x1B[2J\x1B[1;1H", which
fails to clear the scrollback buffer.
The "\E[H\E[2J\E[3J" sequence works on MacOS (Sonoma) (using printf);
I'm not able to test on Windows.
Closes https://github.com/denoland/deno/issues/26514