split off -Ts from -Tj

there is actually no use case overlap between between the two (though
limiting the step count does imply keeping the journal, as we exit
before we could commit anyway).

src/main.c

@@ -430,6 +430,8 @@ main( int argc, char **argv )
 					break;
 				case 'j':
 					DFlags |= KEEPJOURNAL;
+					break;
+				case 's':
 					JLimit = strtol( ochar, &ochar, 10 );
 					break;
 				case 'z':

src/run-tests.pl

@@ -834,7 +834,7 @@ sub test_impl($$$$)
 	for (my $l = 1; $l <= $njl; $l++) {
 		mkchan($sx);
 
-		my ($nxc, $nret) = runsync($async, "-Tj$l", "4-interrupt.log");
+		my ($nxc, $nret) = runsync($async, "-Ts$l", "4-interrupt.log");
 		if ($nxc != (100 + ($l & 1)) << 8) {
 			print "Interrupting at step $l/$njl failed.\n";
 			print "Debug output:\n";