Prevent merged config array ballooning in memory (#5873)
Prevent merged config array ballooning in memory (#5873)

* Prevent merged config array ballooning in memory 

Closes https://github.com/Codeception/Codeception/issues/5817

This change prevents an issue where the config array gets duplicated every time the mergeConfigs array is called causing the array to balloon in size in memory and the test suite to slow down as it progresses.

Original issue raised by and fix suggested by @tweber68
Original issue

* Use more appropriate function to rekey array

`array_merge()` does provide the same behaviour but is not the appropriate function for this operation.
Codeception/Codeception,Naktibalda/Codeception,Naktibalda/Codeception,Codeception/Codeception,Naktibalda/Codeception