Lower memory

Signed-off-by: Tyler Smalley <tyler.smalley@elastic.co>

.buildkite/scripts/steps/test/jest_parallel.sh

@@ -16,7 +16,7 @@ find src x-pack packages -name jest.config.js -not -path "*/__fixtures__/*" | so
     echo "--- $ node scripts/jest --config $config"
     # TODO: sort by list of test files identified by --listFiles
     # Also allows us to ignore configs with no tests so they can still exist.
-    node --max-old-space-size=8192 ./node_modules/.bin/jest --config $config --runInBand
+    node --max-old-space-size=5632 ./node_modules/.bin/jest --config $config --runInBand
 
     if [ $? -ne 0 ]; then
       exitCode=10