- Enabled the feature
- Removed restriction from SpirvShader::getImageSampler()
- Added support for it in SpirvShader::convertFilterMode()

The rest of the logic to compute anisotropic filtering was
still there.

Tests: dEQP-VK.texture.filtering_anisotropy.*
Bug: b/146438763
Change-Id: I2a36d00b6da88091202abe6d4f4f7f9b49507eb3
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/39668
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>