[gardening] Make info_macos_test resilient to snapshots running.

Align info_macos_test with info_linux_test in this regard: fix is similar to how #50583 was addressed.

BUG=#52658
BUG=#52402

TEST=ci

Change-Id: If7ab54990069c86eb5c0348e20086254818da839
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/312705
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Alexander Aprelev <aam@google.com>

Author: aam

pkg/dartdev/test/commands/info_macos_test.dart

@@ -21,7 +21,12 @@ void main() {
         expect(process.memoryMb, greaterThan(0));
         expect(process.cpuPercent, greaterThanOrEqualTo(0.0));
         expect(process.elapsedTime, isNotEmpty);
-        expect(process.commandLine, startsWith('dart'));
+        if (!(process.commandLine.startsWith('dart') ||
+            process.commandLine.contains('snapshot'))) {
+          print("Expected ${process.commandLine} to start with 'dart' or"
+              " contain 'snapshot'.");
+          expect(true, false);
+        }
       }
     });