RFR: 7903936: Update variable names in build.sh documentation

[Christian Stein]

On Tue, 7 Jan 2025 16:04:39 GMT, Oleksii Sylichenko <duke at openjdk.org> wrote:

> Changed variable name `CURL_OPTS` to `CURL_OPTIONS` in the documentation block "Some noteworthy control variables" in `build.sh`. 
> 
> `CURL_OPTIONS` is used in the `download_using_curl()` function in `build-support/build-common.sh`.

Thanks for the contribution @asilichenko!

- Please update this pull request to also include the changes from #239 and close #239 in favor of this pull request.
- Please update the title of this pull request to read: `7903936: Update variable names in build.sh documentation` , I created https://bugs.openjdk.org/browse/CODETOOLS-7903936 for this renaming task.
- Please update the second year in line 4 of `build.sh` from `2024` to `2025`.

-------------

PR Comment: https://git.openjdk.org/jtreg/pull/238#issuecomment-2605094427