Add WebGLSampler support
Reference: https://www.khronos.org/registry/webgl/specs/latest/2.0/#3.7.13
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cc @jdm @zakorgy
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This patch adds initial support for WebGLSync.
Note:
There is no test for the isSync, deleteSync and waitSync functions in the `conformance2/sync/sync-webgl-specific.html`.
Migrate to IDL mixin syntax
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- [x] These changes fix#22539
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