[32-bit Linux] Investigate Linear Algebra failure
https://github.com/mratsim/Arraymancer/pull/510/checks?check_run_id=2980291716#step:21:823

![image](https://user-images.githubusercontent.com/22738317/124365746-40ee9400-dc4a-11eb-9e4e-92d8c6725a84.png)


The first failure may be due to rounding issue with float32 and switching to float64 will solve the issue.
1e-11 is way over float32 precision.

https://github.com/mratsim/Arraymancer/blob/8514e78993ea5852eb8c4d45f00cfbf13b3e193f/tests/linear_algebra/test_linear_algebra.nim#L130-L147

The second issue is very strange though https://github.com/mratsim/Arraymancer/blob/8514e78993ea5852eb8c4d45f00cfbf13b3e193f/tests/linear_algebra/test_linear_algebra.nim#L300-L326