Fix emscripten tests

Author: alexcrichton

src/test/ui/cfg/cfg-target-family.rs

@@ -4,13 +4,10 @@
 // pretty-expanded FIXME #23616
 
 #[cfg(target_family = "windows")]
-pub fn main() {
-}
+pub fn main() {}
 
 #[cfg(target_family = "unix")]
-pub fn main() {
-}
+pub fn main() {}
 
-#[cfg(target_family="wasm")]
-pub fn main() {
-}
+#[cfg(all(target_family = "wasm", not(target_os = "emscripten")))]
+pub fn main() {}