[vm] Several unit tests are corrected for limited ints

runtime/vm/dart_api_impl_test.cc

Index: runtime/vm/dart_api_impl_test.cc
diff --git a/runtime/vm/dart_api_impl_test.cc b/runtime/vm/dart_api_impl_test.cc
index 5b50d6eb731862bd9805aed1ac272462e7b3894f..219dc10a4f151bd6577ebd0245687f154c090156 100644
--- a/runtime/vm/dart_api_impl_test.cc
+++ b/runtime/vm/dart_api_impl_test.cc
@@ -5340,7 +5340,7 @@ static void NativeArgumentAccess(Dart_NativeArguments args) {
 
     EXPECT(arg_values[1].as_int32 == 77);
 
-    EXPECT(arg_values[2].as_uint64 == 0xffffffffffffffffLL);
+    EXPECT(arg_values[2].as_uint64 == 0x8000000000000000LL);

[alexmarkov, 2017/07/31 23:35:18]

Note: this particular value is chosen for the following reasons.
1) When wrapped-around, it should not fit into int32, because this unit test
verifies that getting it as int32 produces error. The original value MaxUint64
does not work for this reason, as it wraps around to -1.
2) It should be large enough to exercise Bigints with unlimited ints, so it
should be > MaxInt64.
Given these constraints, any value between MaxInt64+1 and MaxUint64-MaxInt32-1
would work. Value 0x8000000000000000 is in this range and easy to produce
without using a large integer literal.

[zra, 2017/08/01 16:13:49]

I think this would be good to add as a comment in the code.

[alexmarkov, 2017/08/01 16:25:43]

Done.

 
     EXPECT(arg_values[3].as_bool == true);
 
@@ -5446,7 +5446,7 @@ TEST_CASE(GetNativeArguments) {
       "  MyObject obj1 = MyObject.createObject();"
       "  MyObject obj2 = MyObject.createObject();"
       "  return obj1.accessFields(77,"
-      "                           0xffffffffffffffff,"
+      "                           1 << 63,"
       "                           true,"
       "                           3.14,"
       "                           str,"