[tests] Update some tests for web numbers

Change-Id: I6cf7925779a93cae082e23c2bdf15ac36016eeb5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/333127
Reviewed-by: Mark Zhou <markzipan@google.com>
Commit-Queue: Stephen Adams <sra@google.com>

tests/language/number/numbers_test.dart

@@ -13,18 +13,18 @@ class NumbersTest {
     Expect.equals(true, one is Object);
     Expect.equals(true, one is num);
     Expect.equals(true, one is int);
-    Expect.equals(false, one is double);
+    Expect.equals(webNumbers, one is double);
 
     var two = 2.0;
     Expect.equals(true, two is Object);
     Expect.equals(true, two is num);
-    Expect.equals(false, two is int);
+    Expect.equals(webNumbers, two is int);
     Expect.equals(true, two is double);
 
     var result = one + two;
     Expect.equals(true, result is Object);
     Expect.equals(true, result is num);
-    Expect.equals(false, result is int);
+    Expect.equals(webNumbers, result is int);
     Expect.equals(true, result is double);
 
     Expect.equals(3.0, result);

tests/language/operator/truncdiv_zero_test.dart

@@ -9,6 +9,11 @@ import "package:expect/expect.dart";
 import "truncdiv_test.dart" as truncdiv_test show foo, foo2;
 
 main() {
-  Expect.throws<UnsupportedError>(() => truncdiv_test.foo(12, 0));
+  if (!webNumbers) {
+    Expect.throws<UnsupportedError>(() => truncdiv_test.foo(12, 0));
+  } else {
+    // Web numbers consider infinities to be large-magnitide 'int' values.
+    truncdiv_test.foo(12, 0);
+  }
   Expect.throws<UnsupportedError>(() => truncdiv_test.foo2(0));
 }