Remove the unnecessary < 1.9 checks

[codecov[bot]]

Codecov Report

Attention: 7 lines in your changes are missing coverage. Please review.

Comparison is base (e712202) 64.10% compared to head (97ff64b) 66.31%.

Files	Patch %	Lines
src/factorization.jl	86.79%	7 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #439 +/- ## ========================================== + Coverage 64.10% 66.31% +2.21% ========================================== Files 27 27 Lines 2106 2019 -87 ========================================== - Hits 1350 1339 -11 + Misses 756 680 -76 ```

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[avik-pal]

@ChrisRackauckas this is good to go