Fix test timeout: common.speculation.t_dtrace_contrib.tst_NoSpecBuffer_d

[lwhsu]

Summary

This test timeout on a quiet system because there is nobody triggers
syscall::open:entry and syscall::: probe while test execution.

Add a simple script to generate some noise, it sleeps for 1 second at begining
because current dtest script doesn't support execute a program after invoking
dtrace script.

Test Plan

cd /usr/tests/cddl/usr.sbin/dtrace/common/speculation && kyua debug t_dtrace_contrib:tst_NoSpecBuffer_d

[ngie]

Why is a binary file being checked in?

[lwhsu]

In D11671#241800, @ngie wrote:

Why is a binary file being checked in?

That's not a binary file, it's a script which needs to be run while test running, like other .exe files in test suite. arc(1) treats it as binary...

[lwhsu]

svn ps svn:mime-type text/plain tst.NoSpecBuffer.exe

[markj]

cddl/contrib/opensolaris/cmd/dtrace/test/tst/common/speculation/tst.NoSpecBuffer.exe

27 ↗

(On Diff #31016)

This is susceptible to the same race I mentioned in the other review. IMO it is better to just loop forever and let the test harness kill the .exe process once the test has passed.

[lwhsu]

Use infinite loop

[lwhsu]

Add a sleep(1) to avoid CPU busy loop.