fix: windows test errors

[marcuspang]

Relevant issue: #541

Description

The bundle test was an easy fix, but the rounding differences for some color mix minify tests seem to boil down to how the different OSes handle floating point arithmetic.

After some debugging for this test,

minify_test(
  ".foo { color: color-mix(in lch, peru 40%, palegoldenrod); }",
  ".foo{color:lch(79.7255% 40.4542 84.7634)}",
);

I noticed that p1 and p2 in src\values\color.rs (L2875) don't end up with 0.4 and 0.6, unlike my Unix build.

Couldn't really figure out why the class names were being converted differently either, so I'll only be adding the fix to the bundle.test.mjs file.

Changes

• replace \ with / for paths used in in-memory filesystem tests (for yarn test)