Fix fallout

Author: edwardw

src/test/compile-fail/range-1.rs

@@ -17,10 +17,7 @@ pub fn main() {
 
     // Float => does not implement iterator.
     for i in 0f32..42f32 {}
-    //~^ ERROR `core::iter::Iterator` is not implemented for the type `core::ops::Range<f32>`
-    //~^^ ERROR
-    //~^^^ ERROR
-    // FIXME(#21528) not fulfilled obligation error should be reported once, not thrice
+    //~^ ERROR the trait `core::num::Int` is not implemented for the type `f32`
 
     // Unsized type.
     let arr: &[_] = &[1us, 2, 3];