Lower all non-memcmp-able array equality comparisons to __equals template

[kinke]

No description provided.

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[kinke]

The CTFE failures of runnable/sdtor.d are caused by https://issues.dlang.org/show_bug.cgi?id=22536.

[RazvanN7]

@kinke Is there anything else besides Issue 22536 blocking this PR? I see that compilation of phobos is failing with:

std/array.d(1418): Error: incompatible types for array comparison: `C[5]` and `C[5]`

[kinke]

@RazvanN7: Sorry, I don't remember, but I guess then it was just the first hurdle before investigating library unittest failures. Thanks for tackling the CTFE issue btw, much appreciated.

[kinke]

Needs a CTFE fix (#13496?) and then looking into the then-appearing test regressions like that C[5] above (possibly requiring some __equals adaptations in druntime).