runtest: pass timeouts down to tests: use it in one test

A few tests implement their own timeouts to let them see whether dtrace
has started up properly.  This is less than ideal when valgrind is in
use, since that routinely causes startup to slow down by an order of
magnitude.  The runtest script adapts the script-wide timeout, but
this is not passed down to tests so they cannot do the same even if
they wanted to.

So pass down $timeout, and adjust one test that spuriously fails.

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>

runtest.sh

@@ -750,7 +750,7 @@ for dt in $dtrace; do
         base=${base%.sh}
         base=${base%.c}
         testonly="$(basename $_test)"
-        timeout="$TIMEOUT"
+        export timeout="$TIMEOUT"
 
         # Hidden files and editor backup files are not tests.
 

test/unittest/providers/tst.dtrace_cleanup.sh

@@ -20,7 +20,7 @@ out=/tmp/output.$$
 $dtrace $dt_flags -n BEGIN,END &>> $out &
 pid=$!
 
-for iter in 1 2 3 4 5 6; do
+for iter in $(seq 1 $((timeout/2))); do
     sleep 1
     if grep -q :BEGIN $out; then
         iter=0