strace: add a timeout for running ptests

5.2 kernel has introduced a significant performance regression
where some of the tests take many minutes to complete (where
previously it was seconds). While we're getting to the bottom
of the issue and working with upstream to resove it, this
change allows tests to proceed instead of getting stuck and
eventually timing out.

https://bugzilla.yoctoproject.org/show_bug.cgi?id=13506

(From OE-Core rev: 36670f3989ef129d285b2a17c289f8fc7a44b320)

Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/strace/strace/run-ptest

@@ -1,2 +1,3 @@
 #!/bin/sh
+export TIMEOUT_DURATION=30
 make -B -C tests -k test-suite.log