[lldb] [Process/Utility] Update code url for FreeBSD in comments (#178556)
FreeBSD has moved from svn to git. Use https://cgit.freebsd.org/src
instead as it is the source of truth. i386 and mips64 were no longer
supported as of FreeBSD 15 and 14, respectively, so link stable branch
instead of main branch. See [FreeBSD platforms
page](https://www.freebsd.org/platforms/).
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Signed-off-by: Minsoo Choo <minsoochoo0122@proton.me>