Don't expect 0.gcd(0) to throw in bigint test.

tests/corelib/big_integer_arith_vm_test.dart

Index: tests/corelib/big_integer_arith_vm_test.dart
diff --git a/tests/corelib/big_integer_arith_vm_test.dart b/tests/corelib/big_integer_arith_vm_test.dart
index 0d2f5169d92716b41127a62c6312869b99dadc5c..49e6e0dd8e7a977bf8c15fa6539f49337233fc1e 100644
--- a/tests/corelib/big_integer_arith_vm_test.dart
+++ b/tests/corelib/big_integer_arith_vm_test.dart
@@ -322,7 +322,7 @@ testBigintGcd() {
   Expect.equals(-x, x.gcd(m));
   x = 0;
   m = 0;
-  Expect.throws(() => x.gcd(m), (e) => e is ArgumentError);
+  Expect.equals(0, x.gcd(m));
   x = 0;
   m = 123456789012345678901234567890;
   Expect.equals(m, x.gcd(m));
@@ -335,9 +335,6 @@ testBigintGcd() {
   x = -123456789012345678901234567890;
   m = 0;
   Expect.equals(-x, x.gcd(m));
-  x = 0;
-  m = 0;
-  Expect.throws(() => x.gcd(m), (e) => e is ArgumentError);
   x = 1234567890;
   m = 19;
   Expect.equals(1, x.gcd(m));