Update conformance2/buffers/bound-buffer-size-change-test.html to top-of-tree 2.0.0. MozReview-Commit-ID: CgfP70Y0wul
Flattened with: * Clean up generic vertex attribs. - r=bz,daoshengmu * Remove EnsureAttrib() and friends. - r=daoshengmu * Simplify EnumName behavior and usage and add ErrorInvalidEnumArg(). - r=daoshengmu
MozReview-Commit-ID: KXpLbIu8pRr