test: fixed some tests affected by banker's rounding.

Author: lifthrasiir

src/test/run-pass/ifmt.rs

@@ -138,10 +138,10 @@ pub fn main() {
     t!(format!("{:e}", 1.2345e6f32), "1.2345e6");
     t!(format!("{:e}", 1.2345e6f64), "1.2345e6");
     t!(format!("{:E}", 1.2345e6f64), "1.2345E6");
-    t!(format!("{:.3e}", 1.2345e6f64), "1.235e6");
-    t!(format!("{:10.3e}", 1.2345e6f64),   "   1.235e6");
-    t!(format!("{:+10.3e}", 1.2345e6f64),  "  +1.235e6");
-    t!(format!("{:+10.3e}", -1.2345e6f64), "  -1.235e6");
+    t!(format!("{:.3e}", 1.2345e6f64), "1.234e6");
+    t!(format!("{:10.3e}", 1.2345e6f64),   "   1.234e6");
+    t!(format!("{:+10.3e}", 1.2345e6f64),  "  +1.234e6");
+    t!(format!("{:+10.3e}", -1.2345e6f64), "  -1.234e6");
 
     // Float edge cases
     t!(format!("{}", -0.0), "0");