Be stricter in test scripts

Omitting parameters is not a good idea, but even worse if it fails
mysteriously without any error messages

test/fetch-test-deps.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-set -e
+set -euo pipefail
 
 cd "$(dirname "$0")"
 

test/run-tests.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-set -e
+set -euo pipefail
 
 cd "$(dirname "$0")"