Bug1368610 - stylo: implement primitive (bit, uXX) type of discrete animatable properties
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This PR is to fix https://bugzilla.mozilla.org/show_bug.cgi?id=1368610
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
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- [X] There are tests for these changes. The tests will land in dom/animation/test of m-c. Test code is patch 6 of https://bugzilla.mozilla.org/show_bug.cgi?id=1368610
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