webgl/2.0.1/conformance/glsl/misc/shader-with-dfdx.frag.html fails
FAIL [unexpected link status] (expected: false) fragment shader that uses dFdx should fail
https://www.khronos.org/registry/webgl/sdk/tests/conformance/glsl/misc/shader-with-dfdx.frag.html?webglVersion=2&quiet=0&quick=1
At least macOS 11.3, iMacPro1,1, Radeon Pro Vega 56
<rdar://problem/75773876>