Add abnormal hook to determine which tabs to auto-widen

Add abnormal hook to determine which tabs to auto-widen

* lisp/tab-bar.el (tab-bar-auto-width-predicate-default):  Default value
for tab-bar-auto-width-functions.
(tab-bar-auto-width-functions): New abnormal hook.
(tab-bar-auto-width): Run new abnormal hook until success instead of
comparing text properties.

(cherry picked from commit 9ed761a793f0f11ffea1d2cfa9b7ff38a58d3fe1)