Auto merge of #26333 - szeged:mmatyas__webgl_fns_getparam3, r=jdm

Add support for even more WebGL2 GetParameter enums

Adds support for the following new WebGL2 GetParameter values:

- `PACK_ROW_LENGTH`
- `PACK_SKIP_PIXELS`
- `PACK_SKIP_ROWS`
- `RASTERIZER_DISCARD`
- `UNPACK_IMAGE_HEIGHT`
- `UNPACK_ROW_LENGTH`
- `UNPACK_SKIP_IMAGES`
- `UNPACK_SKIP_PIXELS`
- `UNPACK_SKIP_ROWS`

See: https://www.khronos.org/registry/webgl/specs/latest/2.0/#3.7.2

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Depends on #26265 because they touch the same test file.

cc @jdm @zakorgy

---
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] There are tests for these changes

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components/canvas_traits/webgl.rs

@@ -795,6 +795,7 @@ parameters! {
             SampleCoverageInvert = gl::SAMPLE_COVERAGE_INVERT,
             TransformFeedbackActive = gl::TRANSFORM_FEEDBACK_ACTIVE,
             TransformFeedbackPaused = gl::TRANSFORM_FEEDBACK_PAUSED,
+            RasterizerDiscard = gl::RASTERIZER_DISCARD,
         }),
         Bool4(ParameterBool4 {
             ColorWritemask = gl::COLOR_WRITEMASK,
@@ -842,6 +843,14 @@ parameters! {
             MaxTransformFeedbackSeparateComponents = gl::MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS,
             TransformFeedbackBufferSize = gl::TRANSFORM_FEEDBACK_BUFFER_SIZE,
             TransformFeedbackBufferStart = gl::TRANSFORM_FEEDBACK_BUFFER_START,
+            PackRowLength = gl::PACK_ROW_LENGTH,
+            PackSkipPixels = gl::PACK_SKIP_PIXELS,
+            PackSkipRows = gl::PACK_SKIP_ROWS,
+            UnpackImageHeight = gl::UNPACK_IMAGE_HEIGHT,
+            UnpackRowLength = gl::UNPACK_ROW_LENGTH,
+            UnpackSkipImages = gl::UNPACK_SKIP_IMAGES,
+            UnpackSkipPixels = gl::UNPACK_SKIP_PIXELS,
+            UnpackSkipRows = gl::UNPACK_SKIP_ROWS,
         }),
         Int2(ParameterInt2 {
             MaxViewportDims = gl::MAX_VIEWPORT_DIMS,