test-buffer-creation-regression is flaky on some SmartOS hosts in CI,
timing out. Move to sequential so it does not compete with other tests
for resources. Reduce three test cases to just the one needed to
identify the regression.
PR-URL: https://github.com/nodejs/node/pull/10161
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Italo A. Casas <me@italoacasas.com>
Rich Trott