Tests disable register cache

test/support/register.js

@@ -8,11 +8,12 @@
 'use strict';
 
 // Patch filesystem for virtual fixtures files
-const {FIXTURES_DIR_PATH} = require('./fixturesFs.js');
+require('./fixturesFs.js');
 
 // Install register require hook.
-// Don't cache instrumented fixture files. There's way too many of them.
-require('../../register.js')({skipCacheForDir: FIXTURES_DIR_PATH});
+// Disable instrumentation cache. Tests run in multiple threads, so it'd be read from and written to
+// concurrently unless disabled.
+require('../../register.js')({cache: false});
 
 // Use internal module cache to avoid transpiling modules
 const {