Check shaderFloat16 feature support for enabling Float16 in Spirv According to VK_KHR_shader_float16_int8 device extension spec: "It introduces two new optional features shaderFloat16 and shaderInt8 which directly map to the Float16 and the Int8 SPIR-V capabilities." We should check if the shaderFloat16 is supported before we generate SPIRV that declares SPIR-V Capability Float16 Bug: angleproject:405795981 Change-Id: Ied7edfbed81ed5b862907c9bb1e772cb43acdb8b Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6919673 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Xiang Wang <xwxw@google.com>