test: fix flaky test-memory-usage

abe6a2e3 introduced a test that verifies that ArrayBuffer
allocations are tracked. However, V8 supports concurrent freeing
of such allocations on background threads, meaning that the results
may be subject to race conditions sometimes.

Disabling concurrent freeing makes the test pass consistently.

Refs: https://github.com/nodejs/node/pull/31550

PR-URL: https://github.com/nodejs/node/pull/31602


Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>