test: delete pummel/test-dtrace-jsstack

The test pummel/test-dtrace-jsstack is broken and probably has been for
a very long time. Remove it.

It gets skipped on anything that is non-SunOS. In our CI, that means
skipped everywhere but SmartOS.

When run on SmartOS in our CI (which never happens because it's in
pummel, but I moved it into sequential to test it), it fails because it
needs elevated privileges.

When I log into the SmartOS machine and run the test as root, it fails
with:

  AssertionError [ERR_ASSERTION]: did not find expected frame stalloogle

Since I have dtrace installed on my macOS machine, I tried running it
locally but removing the SunOS check. It failed because the test leaks a
global variable. I removed the global leak check, and the test failed
because I have System Integrity Protection enabled.

In short, the test does not work in its current form, has almost
certainly not worked in a long time, and is very likely to be brittle if
we ever do fix it. I'm inclined to remove it.