Refactor float Primitives to a separate Float type

compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs

@@ -122,10 +122,7 @@ fn tag_base_type<'ll, 'tcx>(
             // Niche tags are always normalized to unsized integers of the correct size.
             match tag.primitive() {
                 Primitive::Int(t, _) => t,
-                Primitive::F16 => Integer::I16,
-                Primitive::F32 => Integer::I32,
-                Primitive::F64 => Integer::I64,
-                Primitive::F128 => Integer::I128,
+                Primitive::Float(f) => Integer::from_size(f.size()).unwrap(),
                 // FIXME(erikdesjardins): handle non-default addrspace ptr sizes
                 Primitive::Pointer(_) => {
                     // If the niche is the NULL value of a reference, then `discr_enum_ty` will be