Description:
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setlocale used to return current locale per category when passing null or "0" as locale, but now it's returning the latest set locale.

The actual value for LC_TIME is still 'en_US.UTF8', it's only reporting the wrong value.

Regression since https://github.com/php/php-src/commit/4514ba016ff158cd113deef1a215fcdcb6913b48

Test script:
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var_dump(setlocale(LC_TIME, 'en_US.UTF8'));
var_dump(setlocale(LC_NUMERIC, 'C'));
var_dump(setlocale(LC_TIME, 0));

Expected result:
----------------
string(10) "en_US.UTF8"
string(1) "C"
string(10) "en_US.UTF8"

Actual result:
--------------
string(10) "en_US.UTF8"
string(1) "C"
string(1) "C"