[dart2wasm] Fix isNegative on NaN values

New passing tests:

- co19/LibTest/core/double/isNegative_A01_t01
- corelib/nan_infinity_test/01
- corelib/nan_infinity_test/none
- language/unsorted/intrinsified_methods_test

Change-Id: I379525fe0da36d6fc365d275ded9370f2b5b4812
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/274541
Reviewed-by: Aske Simon Christensen <askesc@google.com>
Commit-Queue: Ömer Ağacan <omersa@google.com>

sdk/lib/_internal/wasm/lib/double.dart

@@ -137,6 +137,9 @@ class _BoxedDouble extends double {
   bool operator <=(num other) => this <= other.toDouble(); // Intrinsic <=
 
   bool get isNegative {
+    if (isNaN) {
+      return false;
+    }
     int bits = doubleToIntBits(this);
     return (bits & _signMask) != 0;
   }