test_cmake_out_of_source: validate that ssl-opt passed

If the ssl-opt test case was skipped, the test was ineffective.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 6677b20..2908e98 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -2983,11 +2983,12 @@
     # "No such file or directory", which would indicate that some required
     # file is missing (ssl-opt.sh tolerates the absence of some files so
     # may exit with status 0 but emit errors).
-    ./tests/ssl-opt.sh -f 'Fallback SCSV: beginning of list' 2>ssl-opt.err
+    ./tests/ssl-opt.sh -f 'Fallback SCSV: beginning of list' >ssl-opt.out 2>ssl-opt.err
+    grep PASS ssl-opt.out
     cat ssl-opt.err >&2
     # If ssl-opt.err is non-empty, record an error and keep going.
     [ ! -s ssl-opt.err ]
-    rm ssl-opt.err
+    rm ssl-opt.out ssl-opt.err
     cd "$MBEDTLS_ROOT_DIR"
     rm -rf "$OUT_OF_SOURCE_DIR"
 }