gen_zig.py: remove obsolete stage1 check

bindgen/gen_zig.py

@@ -456,10 +456,7 @@ def gen_helpers(inp):
         l('            }')
         l('        },')
         l('        .Struct, .Array => {')
-        l('            switch (builtin.zig_backend) {')
-        l('                .stage1 => return .{ .ptr = &val, .size = @sizeOf(@TypeOf(val)) },')
-        l('                else => @compileError("Structs and arrays must be passed as pointers to asRange"),')
-        l('            }')
+        l('            @compileError("Structs and arrays must be passed as pointers to asRange");')
         l('        },')
         l('        else => {')
         l('            @compileError("Cannot convert to range!");')