Fix 'Skip' behavior in erts files (bug#76839)

* lisp/emacs-lisp/ert.el (ert-test--erts-test): Fix 'Skip'
behavior in erts files, so only the test case where it is
specified is skipped.
* test/lisp/emacs-lisp/ert-tests.el (ert-test-erts-skip-one)
(ert-test-erts-skip-last): Add test cases.

test/lisp/emacs-lisp/ert-resources/erts-skip-last.erts

@@ -0,0 +1,8 @@
+Name: last
+Skip: t
+
+=-=
+FOO
+=-=
+BAR
+=-=-=

test/lisp/emacs-lisp/ert-resources/erts-skip-one.erts

@@ -0,0 +1,16 @@
+Name: first
+Skip: t
+
+=-=
+FOO
+=-=
+FOO
+=-=-=
+
+Name: second
+
+=-=
+FOO
+=-=
+BAR
+=-=-=

test/lisp/emacs-lisp/ert-tests.el

@@ -28,6 +28,7 @@
 
 (require 'cl-lib)
 (require 'ert)
+(require 'ert-x)
 
 ;;; Self-test that doesn't rely on ERT, for bootstrapping.
 
@@ -1029,6 +1030,17 @@ F failing-test
                  (ert-with-test-buffer (:name "foo" :selected t)
                    (buffer-name)))))
 
+(ert-deftest ert-test-erts-skip-one ()
+  "Test that Skip does not affect subsequent test cases (Bug#76839)."
+  (should-error (ert-test-erts-file (ert-resource-file "erts-skip-one.erts")
+                                    (lambda () ()))
+                :type 'ert-test-failed))
+
+(ert-deftest ert-test-erts-skip-last ()
+  "Test that Skip does not fail on last test case (Bug#76839)."
+  (ert-test-erts-file (ert-resource-file "erts-skip-last.erts")
+                      (lambda () ())))
+
 (provide 'ert-tests)
 
 ;;; ert-tests.el ends here