[release/dev17.14] Update field value for NavBar Integration Tests (#79076)

Backport of #78553 and #78532 to
release/dev17.14

/cc @phil-allen-msft @akhera99

Author: jasonmalinowski

src/VisualStudio/IntegrationTest/New.IntegrationTests/InProcess/EditorInProcess.cs

@@ -566,7 +566,14 @@ private async Task<List<ComboBox>> GetNavigationBarComboBoxesAsync(IWpfTextView
         await JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
 
         var margin = await GetNavigationBarMarginAsync(textView, cancellationToken);
-        return margin.GetFieldValue<List<ComboBox>>("_combos");
+        try
+        {
+            return margin.GetFieldValue<List<ComboBox>>("_combos");
+        }
+        catch (FieldAccessException)
+        {
+            return margin.GetFieldValue<List<ComboBox>>("Combos");
+        }
     }
 
     private async Task<UIElement?> GetNavigationBarMarginAsync(IWpfTextView textView, CancellationToken cancellationToken)

src/Workspaces/CoreTestUtilities/ObjectExtensions.cs

@@ -46,7 +46,7 @@ public static object GetFieldValue(this object instance, string fieldName)
 
             if (fieldInfo == null)
             {
-                throw new FieldAccessException("Field " + fieldName + " was not found on type " + type.ToString());
+                throw new FieldAccessException($"Field '{fieldName}' was not found on type '{instance.GetType()}'");
             }
 
             var result = fieldInfo.GetValue(instance);