Don't throw during cleanup if test class directory does not exist (Azure#34909)

Author: JoshLove-msft

sdk/core/Azure.Core.TestFramework/src/RecordedTestBase.cs

@@ -352,6 +352,12 @@ public void TearDownRecordedTestClass()
             // Clean up unused test files
             if (Mode == RecordedTestMode.Record)
             {
+                var testClassDirectory = new DirectoryInfo(GetSessionFileDirectory());
+                if (!testClassDirectory.Exists)
+                {
+                    return;
+                }
+
                 var knownMethods = new HashSet<string>();
 
                 // Management tests record in ctor
@@ -373,7 +379,7 @@ public void TearDownRecordedTestClass()
                     knownMethods.Add(method.Name);
                 }
 
-                foreach (var fileInfo in new DirectoryInfo(GetSessionFileDirectory()).EnumerateFiles())
+                foreach (var fileInfo in testClassDirectory.EnumerateFiles())
                 {
                     bool used = knownMethods.Any(knownMethod => fileInfo.Name.StartsWith(knownMethod, StringComparison.CurrentCulture));