tu/blit: Don't set CLAMPENABLE in sampler for 3d path
This was copied from the blob before we understood what it did, and it has questionable utility: there's nothing in the GL, Vulkan, or D3D11 specs that require the result be clamped to the underlying range to account for imprecision. And it doesn't make sense at all for cubic filtering, because the result can legitimately be outside the range in some scenarios. Just remove it. This fixes a bunch of tests added in vulkan CTS 1.2.8 to test blitting from compressed textures, which use random inputs and therefore are more likely to hit the out-of-range condition. For example, dEQP-VK.api.copy_and_blit.core.blit_image.all_formats.color.2d.etc2_r8g8b8a8_unorm_block.r8g8b8a8_snorm.general_general_cubic.