Remove static caching of static on Contribution page tab

[mattwire]

Overview

This one is for @eileenmcnaughton ... Remove the static caching on a static function.

Before

Unnecessary code, less comments

After

Cleaner code, comments/docblocks cleaned up

Technical Details

This cleans up an early return + static caching of the recurLinks() function which is already static.

Comments

[civibot]

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[seamuslee001]

Jenkins re test this please

[totten]

I think I like this, but the rationale ("unnecessary") seemed hand-wavy. Trying to read between the lines...

Caching that initial array of 3 elements looks a lot like a micro-optimization. The micro-optimization might make sense if, hypothetically, ::recurLinks() was called 10,000 times in some pageview. But that hypothetical seems only hypothetical; and even if that use-case is conceded, the expected gain doesn't bear-out in benchmarking on php7. (Make a throw-away script which calls recurLinks() 10k times and compare with/without $_links).

+1 for simpler code

[mattwire]

@totten Thanks :-) @eileenmcnaughton particularly doesn't like the static $_links, I didn't mind. But it does simplify the code without!

[mattwire]

@eileenmcnaughton Please review comments and merge if you are happy?

[eileenmcnaughton]

I worked through the refactor & it seems fine - links still exist on the recurring contribution tab