Fix warnings_checker.dart handling of multitests

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 a992b9440d5646c2c666e91f914bc44ee2e86f19..60c339a9e0339870c8879c6ff0e8ad2763cc5876 100644
--- a/tests/corelib/big_integer_arith_vm_test.dart
+++ b/tests/corelib/big_integer_arith_vm_test.dart
@@ -422,18 +422,18 @@ main() {
   for (int i = 0; i < 10; i++) {
     Expect.equals(1234567890123456789, foo());
     Expect.equals(12345678901234567890, bar());
-    testSmiOverflow(); // /// overflow: ok
-    testBigintAdd(); // /// add: ok
-    testBigintSub(); // /// sub: ok
-    testBigintMul(); // /// mul: ok
-    testBigintTruncDiv(); // /// trunDiv: ok
-    testBigintDiv(); // /// div: ok
-    testBigintModulo(); // /// mod: ok
-    testBigintModPow(); // /// modPow: ok
-    testBigintModInverse(); // /// modInv: ok
-    testBigintGcd(); // /// gcd: ok
-    testBigintNegate(); // /// negate: ok
-    testShiftAmount(); // /// shift: ok
+    testSmiOverflow(); // //# overflow: ok
+    testBigintAdd(); // //# add: ok
+    testBigintSub(); // //# sub: ok
+    testBigintMul(); // //# mul: ok
+    testBigintTruncDiv(); // //# trunDiv: ok
+    testBigintDiv(); // //# div: ok
+    testBigintModulo(); // //# mod: ok
+    testBigintModPow(); // //# modPow: ok
+    testBigintModInverse(); // //# modInv: ok
+    testBigintGcd(); // //# gcd: ok
+    testBigintNegate(); // //# negate: ok
+    testShiftAmount(); // //# shift: ok
     Expect.equals(12345678901234567890, (12345678901234567890).abs());
     Expect.equals(12345678901234567890, (-12345678901234567890).abs());
     var a = 10000000000000000000;