The tests are designed for this, and trying to accommodate 32-bit
platforms is difficult. Size concerns due to element packing and holes
are less of a problem on 32-bit platforms in any event.
Make size_of tests measure stylo and reduce the size of stylo PropertyDeclarations by 16 bytes
Right now they don't, which means that we have four properties making PropertyDeclaration 16 bytes bigger than it should be.
I'm not sure if there's a better way to get these tests to run against stylo than to hoist them into the properties file, but I couldn't figure it out. This seems good enough.
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/15953)
<!-- Reviewable:end -->
The property may be a shorthand property in which case the declaration block
will contain the expanded longhand properties and values.
MozReview-Commit-ID: KxqlYgbIZqL
