Update valet.sock to be a symlink to an existing valet{version}.sock file

[mattstauffer]

This PR modifies #1198, which is an update of #1192.

In #1192/#1198, valet.sock is always used by the global Valet PHP version, and then Valet sets up valet80.sock etc. for versions of PHP that aren't used globally but are used by isolated sites.

This PR makes it so that every PHP version used by Valet, global or not, sets up a valet{version}.sock file, and the global version is set by simply symlink-ing valet.sock to the version-specific .sock file.

This PR:

• Makes that symlink change
• Catches some work I missed in Multiple/Parallel PHP Version Support for Valet #1192 to the syntax in valet.php
• Cleans up normalizePhpVersion with a regex from @fuelingtheweb; again should've just applied to Multiple/Parallel PHP Version Support for Valet #1192
• Drops the tests that were covering the old pre-symlink behavior

Bugs in testing:

• Somehow I saw valet.sock disappear twice in the middle of my testing, which broke all sites. Re-running valet install fixed it but I'm not sure what deleted it in the first place. I'll try to keep testing.

[mattstauffer]

I haven't tested this yet. Will test before asking for review.

[mattstauffer]

On both of my machines, the first time I ran valet install with this new version, it did correctly rename valet.sock to valet80.sock, but it didn't symlink correctly for some reason.

The symlink only worked after I ran valet install the second time. I wonder if this is a race condition?

[mattstauffer]

I'm also wondering... do we even need a symlink? It's a socket.. there may not actually be anything fancy going on here. It may just need a file to exist, in which case we could just delete the file and make a new one.. not even worry about symlinking?

[mattstauffer]

Current thinking about the symlink situation:

If PHP8.0 is our primary version of PHP that's running
and
we have an isolated site on PHP8.0

They'll be pointing to different socket files that are both intending to represent the same PHP connection
And I think they don't like it. And I think that's why my valet.sock keeps disappearing. I'll be digging into it to see.

[mattstauffer]

Looks like valet.sock was disappearing based on a test that didn't mock the filesystem. @bakerkretzmar & I found it and it's fixed.

[mattstauffer]

Solved this problem: #1201 (comment)

I think at this point this PR is ready for review.

[shengslogar]

This is 🔥! Won't pretend to know the ins-and-outs of how this works, but how hard would it be to add a CLI util to access that running PHP version? (Thinking along the lines of php artisan tinker...)

[NasirNobin]

@shengslogar that's coming soon! checkout #1216

This is 🔥! Won't pretend to know the ins-and-outs of how this works, but how hard would it be to add a CLI util to access that running PHP version? (Thinking along the lines of php artisan tinker...)