Changes

Calc sfc varnce GPUization (#1081)

* Initial loop push for calc_sfc_varnce

* BIT_CHANGING:3b086a40085284aa49c71d32c001d20153a8ddb4 the last commit is bit changing for only some cases and only when using higher than -02 optimization. uf min seems to be the first calculation that starting to differ bitwise. Using the check_multicol script confirms the differences are small.

* Adding a tweak to surface values in the extra columns. This helped me check calc_sfc_varance, since we were not changing any arrays that would've affected calculations there.

* Small optimization, making wstar and ustar2 scalars.

* GPUizing calc_sfc_varnce

* Removing conditional around some stats calls. Now we will always save sfc values to stats, because this will change stats files when gr%zm(i,1) > sfc_elevation, this is potentially BIT_CHANGING.

* Merging with latest clubb changes and making work on GPUs again.

This contained 2 commits that are BIT_CHANGING in some situations.