test: run unit tests before integration tests (#1832)

This change:

* will allow a failed unit test to fail the full test pipeline significantly faster than previously
* isolates unit tests from integration tests
* loads less irrelevant files when running mocha test suites (e.g. `test/util/**`, `test/format/**`, `test/data/**` only loaded on demand)
* protects against mistakes like that fixed in #1828

Author: alxndrsn

.mocharc.js

@@ -100,7 +100,8 @@ debug: base
 
 .PHONY: test
 test: lint
-	BCRYPT=insecure npx mocha --recursive
+	$(MAKE) test-unit
+	$(MAKE) test-integration
 
 .PHONY: test-db-migrations
 test-db-migrations:
@@ -110,7 +111,8 @@ test-db-migrations:
 
 .PHONY: test-fast
 test-fast: node_version
-	NODE_CONFIG_ENV=test BCRYPT=insecure npx mocha --recursive --fgrep @slow --invert
+	MOCHA_OPTIONS="--fgrep @slow --invert" $(MAKE) test-unit
+	MOCHA_OPTIONS="--fgrep @slow --invert" $(MAKE) test-integration
 
 .PHONY: test-integration
 test-integration: node_version