Fix Bug#35241

* lisp/files.el (executable-find): Quote default-directory.  (Bug#35241)

* test/lisp/files-tests.el (files-tests-executable-find): New test.
1 job for master in 52 minutes and 27 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Test
failed #1395
test-all

00:52:27

 
Name Stage Failure
failed
test-all Test
Makefile:313: recipe for target 'check-doit' failed
make[2]: *** [check-doit] Error 1
make[2]: Leaving directory '/builds/emacs/emacs/test'
Makefile:288: recipe for target 'check-expensive' failed
make[1]: *** [check-expensive] Error 2
make[1]: Leaving directory '/builds/emacs/emacs/test'
Makefile:962: recipe for target 'check-expensive' failed
make: *** [check-expensive] Error 2
ERROR: Job failed: exit code 1