Vulkan: Drop dependency to VK_EXT_shader_atomic_float This VK extension exposes features that are not necessary for GL_OES_shader_image_atomic. Instead, support for necessary features for VK_FORMAT_R32_SFLOAT is used to determine support for this GL extension. Bug: angleproject:5342 Change-Id: Ia504cba69ffe51cfd7da69df28f58563cb1f0744 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2536908 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Mohan Maiya <m.maiya@samsung.com>