test: add missing implementation-plan test targets

tests/bun_test_test/junit_shape.sh

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+rule_file="$1"
+
+grep -Eq 'exec "\$\{bun_bin\}" test \{src_args\} .*"\$@"' "${rule_file}"
+grep -Eq 'if \[\[ -n "\$\{TESTBRIDGE_TEST_ONLY:-\}" \]\]' "${rule_file}"