Implement `allow-same-frame' for NS drag-and-drop

* lisp/term/ns-win.el (x-begin-drag): Implement
`allow-same-frame'.
* src/nsselect.m (Fns_begin_drag): New parameter
`allow-same-frame'.
* src/nsterm.h (@interface EmacsWindow): Update prototypes.
* src/nsterm.m ([EmacsView draggingEntered:]):
([EmacsView prepareForDragOperation:]):
([EmacsView performDragOperation:]): Respect new parameter.
([EmacsWindow beginDrag:forPasteboard:withMode:returnFrameTo:]):
Likewise.
3 jobs for master in 37 minutes and 24 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build Images
failed #46567
build-image-inotify

00:37:24

 
  Normal
skipped #46568
test-lisp-term-inotify
skipped #46569
test-src-inotify
 
Name Stage Failure
failed
build-image-inotify Build Images
 > [emacs-inotify 5/5] RUN make bootstrap:
------
executor failed running [/bin/sh -c make bootstrap]: exit code: 2
Running after script...
$ test -n "$(docker ps -aq -f name=${test_name})" && docker cp ${test_name}:checkout/test ${test_name}
$ test -n "$(docker ps -aq -f name=${test_name})" && docker rm ${test_name}
$ find ${test_name} ! \( -name "*.log" -o -name ${EMACS_TEST_JUNIT_REPORT} \) -type f -delete
find: build-image-inotify-76850b26: No such file or directory
ERROR: Job failed: exit code 1