Skip the skwasm unit test suite on Safari since it is flaky.

Author: eyebrowsoffire

lib/web_ui/dev/steps/run_tests_step.dart

@@ -100,7 +100,9 @@ class RunTestsStep implements PipelineStep {
       );
     }
 
-    if (sortedTests.skwasmTests.isNotEmpty) {
+    // For some reason, Safari is flaky when running the Skwasm test suite
+    // See https://github.com/flutter/flutter/issues/115312
+    if (browserName != kSafari &&  sortedTests.skwasmTests.isNotEmpty) {
       await _runTestBatch(
         testFiles: sortedTests.skwasmTests,
         renderer: Renderer.skwasm,