Remove bigint reference in js_number.dart

sdk/lib/_internal/compiler/js_lib/js_number.dart

Index: sdk/lib/_internal/compiler/js_lib/js_number.dart
diff --git a/sdk/lib/_internal/compiler/js_lib/js_number.dart b/sdk/lib/_internal/compiler/js_lib/js_number.dart
index 0c13b8f11d2ed98b897ff1aee64eac884756020b..0648aad12d6678319908e4bf37abd0cf70ed5395 100644
--- a/sdk/lib/_internal/compiler/js_lib/js_number.dart
+++ b/sdk/lib/_internal/compiler/js_lib/js_number.dart
@@ -415,9 +415,6 @@ class JSInt extends JSNumber implements int, double {
   int modInverse(int m) {
     if (m is! int) throw new ArgumentError(m);
     if (m <= 0) throw new RangeError(m);
-    if (m is _Bigint) {
-      return _toBigint().modInverse(m);
-    }
     bool ac = m.isEven;
     int u = m;
     int v = this;