don't spawn processes on wasm

Author: oli-obk

src/test/run-pass/invalid_const_promotion.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// ignore-wasm
+
 #![feature(const_fn)]
 #![allow(const_err)]