Rf/autoindentpaste improvements (#30755)
* REPL: disable auto-indent when code is likely being pasted (fix #25186)
On some Windows terminals, pasting is not recognized as such.
This happens also with tmux' builtin paste.
In those cases, auto-indent is better disabled, as we want
to preserve the original indentation of the code being pasted.
This fix is quite a hack, but seems to work: using time(), if
the next character after a newline is being inserted very fast,
assume this was with paste, and cancel the insertion of the
spaces done by auto-indent.
I couldn't insert two characters in a raw within less than
about 0.03 or 0.02 seconds, so the threshold for "very fast"
is set to 0.0005, but this is an option which can changed.
* fix tests
* more reliability
* don't include refresh_line in the timings
* use a separate autoindent variable, as we want to undo indent in case of paste only
for auto-indented code (although currently in the REPL code this function is never
called with a positive argument)
* Some improvements: autoident is now prevented and needs not to be redone. Paste of mixed space/tabs/empty lines is now more reliable.
* fixed bug where indent is set externally
