Remove instances of LOWER casing searches from sort_name, display_name

[eileenmcnaughton]

Overview

Improve performance and reliability of searches involving sort_name & display_name (under some circumstances) by relying on mysql to handle case.

Before

We actively convert the string to use lower case in php and then use mysql LOWER for the comparison

After

We let mysql do what it does well. Test added

Technical Details

Per #12494 mysql handles lcase.

Adding LOWER to mysql queries makes them slower. lowercasing php strings
breaks under some character sets with some server configs. Less is more

Comments

@seamuslee001 @monishdeb @colemanw I think we should push through on these since we have been chipping away for a few months after this discussion #12494 with no fallout

[civibot]

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[seamuslee001]

Code change looks sensible here, again there should be enough coverage of this change in the unit tests to prevent regression, Jenkins has passed. Merging