Remove f16 const eval crash test

Const eval negation was added. This test is now covered by Miri tests
and a new library test.

Fixes <rust-lang#124583>

library/std/src/f128/tests.rs

@@ -38,3 +38,9 @@ macro_rules! assert_f128_biteq {
         );
     };
 }
+
+#[test]
+fn test_neg_zero() {
+    // only verify const eval negation until we add the rest of the checks
+    let _neg_zero: f128 = -0.0;
+}

library/std/src/f16/tests.rs

@@ -44,3 +44,9 @@ macro_rules! assert_f16_biteq {
         );
     };
 }
+
+#[test]
+fn test_neg_zero() {
+    // only verify const eval negation until we add the rest of the checks
+    let _neg_zero: f16 = -0.0;
+}