fix: Add safe directory for environment tests (#1131)

Recently some of PR environment tests started to fail with:
`fatal: detected dubious ownership in repository at '/tmpfs/src/github/java-logging'`
Adding the safe directory for Java

Author: losalex

.kokoro/environment_tests.sh

@@ -27,6 +27,7 @@ fi
 # make sure submodule is up to date
 cd "$PROJECT_ROOT"
 git config --global --add safe.directory '*'
+git config --global --add safe.directory /tmpfs/src/github/java-logging
 git submodule update --init --recursive
 cd "${PROJECT_ROOT}/env-tests-logging"