cirrus: Customize the disabled tests per FreeBSD version

Try to run as many test cases as possible on each OS version.
12.0 passes 13 more tests than the older versions, so we might as well
run them.

.cirrus.yml

@@ -25,8 +25,12 @@ task:
     # Some tests won't run if run as root so run them as another user.
     # Make directories world writable so the test step can write wherever it needs.
     - find . -type d -exec chmod 777 {} \;
-    # TODO: A number of tests are failing on FreeBSD and so are disabled.
-    # This should be investigated.
-    - sudo -u nobody make V=1 TFLAGS='-n -a -p !flaky !303 !304 !310 !311 !312 !313 !323 !504 !1082 !1242 !1243 !2002 !2003 !2034 !2035 !2037 !2038 !2041 !2042 !2048 !3000 !3001' test-nonflaky
+    # TODO: A number of tests are failing on different FreeBSD versions and so
+    # are disabled.  This should be investigated.
+    - SKIP_TESTS=''
+    - if [ `uname -r` = "12.0-RELEASE" ] ; then SKIP_TESTS='!303 !304 !323 !504 !1242 !1243 !2002 !2003'; fi
+    - if [ `uname -r` = "11.2-RELEASE" ] ; then SKIP_TESTS='!303 !304 !310 !311 !312 !313 !504 !1082 !1242 !1243 !2002 !2003 !2034 !2035 !2037 !2038 !2041 !2042 !2048 !3000 !3001'; fi
+    - if [ `uname -r` = "10.4-RELEASE" ] ; then SKIP_TESTS='!303 !304 !310 !311 !312 !313 !504 !1082 !1242 !1243 !2002 !2003 !2034 !2035 !2037 !2038 !2041 !2042 !2048 !3000 !3001'; fi
+    - sudo -u nobody make V=1 TFLAGS="-n -a -p !flaky ${SKIP_TESTS}" test-nonflaky
   install_script:
     - make V=1 install