Regenerated negative_numbers test via ruby sass 3.4.7

https://github.com/sass/libsass/issues/629
https://github.com/sass/libsass/pull/716
Updated spec for passing map as variable arguments to use quoted keys as well
Merge pull request #171 from HugoGiraudel/update_spec_quoted_map_keys

Added spec for LibSass issue 721
Merge pull request #162 from mgreter/fix/fractional-truncated-zeros

Regenerated negative_numbers test via ruby sass 3.4.7
Color: Test case for sass/libsass#730.