Add hooks for after tab open, before close, and to prevent closing

* lisp/tab-bar.el (tab-bar-tab-post-open-functions,
tab-bar-tab-prevent-close-functions, tab-bar-tab-pre-close-functions):
New defcustoms
(tab-bar-new-tab-to, tab-bar-close-tab): Use new defcustoms
1 job for master in 64 minutes and 48 seconds (queued for 7 seconds)
Status Job ID Name Coverage
failed #4455


Name Stage Failure
test-all Test
Makefile:319: recipe for target 'check-doit' failed
make[2]: *** [check-doit] Error 1
make[2]: Leaving directory '/builds/emacs/emacs/test'
Makefile:294: recipe for target 'check-expensive' failed
make[1]: *** [check-expensive] Error 2
make[1]: Leaving directory '/builds/emacs/emacs/test'
Makefile:959: recipe for target 'check-expensive' failed
make: *** [check-expensive] Error 2
ERROR: Job failed: exit code 1