WGSL: Ternary operator emitted

[aleino-nv]

Affected tests:

• tests/autodiff-dstdlib/dstdlib-abs.slang

WGPU errors:

WGPU error: Error while parsing WGSL: :11:47 error: invalid character found
    var _S1 : f32 = ((*dpx_0).primal_0 > 0.0f ? 1.0f : (*dpx_0).primal_0 == 0.0f ? 0.0f : -1.0f) * dOut_0;