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Adds support for the other overload of bufferData, fixing many conformance tests. In the process I had to fix the webidl codegen in the overload-distinguished-by-an-object case. Also includes a little fix for glEnable() validation.
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- [ ] These changes fix #__ (github issue number if applicable).
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Source-Repo: https://github.com/servo/servo
Source-Revision: 4216c16879efb6e87b3ba3b7b4d5c2aeb8e2739d