fix: npm script check:test failure on ubuntu

A bug was introduced with the recent npm script changes on Ubuntu
This expands a glob used that isn't supported by the default shell

NODE-2542

Author: nbbeeken

package.json

@@ -72,9 +72,9 @@
     "build:types": "tsc",
     "check:atlas": "node test/tools/atlas_connectivity_tests.js",
     "check:bench": "node test/benchmarks/driverBench",
-    "check:coverage": "nyc mocha --timeout 60000 --recursive test/{functional,unit}",
+    "check:coverage": "nyc mocha --timeout 60000 --recursive test/functional test/unit",
     "check:lint": "eslint index.js lib test",
-    "check:test": "mocha --recursive test/{functional,unit}",
+    "check:test": "mocha --recursive test/functional test/unit",
     "check:types": "tsc -p tsconfig.check.json",
     "release": "standard-version -i HISTORY.md",
     "test": "npm run check:lint && npm run check:test"