Full grid is overriden to symmetric grid

[unalmis]

When I make a compute function with

resolution_requirement="tz",
grid_requirement={"coordinates": "rtz", "is_meshgrid": True, "sym": False}

and use eq.compute for that function, the full grid I supply is overridden to a symmetric one. The compute function catches this error, complaining that a full grid is required.

In general, I should not need to specify override_grid=False here because I am fine with the grid being overriden when computing dependencies.

[unalmis]

#1094 is a good branch to resolve this because it has quantities that require non-symmetric grids