test: add regex to assert in zlib-write-after-close

docs for assert.throws() allows the addition of a regular expression argument.

test/parallel/test-zlib-write-after-close.js line 9 contains an assert.throws() call which only has a single argument.

Per NodeToDo have added regex argument to the assert.throws() call to validate received error message.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• commit message follows commit guidelines

Affected core subsystem(s)

test