test: remove duplicate test-child-process-execfilesync-maxBuffer.js

[joyeecheung]

In addition correct the comment about what it does.

This is produced by

mv test/parallel/test-child-process-execfilesync-maxBuffer.js test/parallel/test-child-process-execfilesync-maxbuf.js 

If you use https://github.com/nodejs/node/pull/28139/files?w=1 to view the diff you can see they aren't doing anything too different.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

[nodejs-github-bot]

Sadly, an error occurred when I tried to trigger a build. :(

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/23721/

[Trott]

Micro-nit: Is maxBuffer perhaps the ever-so-slightly better file name part since it clearly reflects what's being tested? (Like, if someone is looking for maxBuffer tests, they might do a case-insensitive grep for filenames with maxBuffer and miss it if it's maxbuf instead?)

[joyeecheung]

@Trott There is also test-child-process-spawnsync-maxbuf.js, and a few other child process tests that do all lower-cases...I guess we should leave that to a future PR to change all these?

[joyeecheung]

Landed in e0fa30f