Return false from ComWrappers.Try... methods

Return false from ComWrappers.TryGetComInstance/TryGetObject instead of
throwing PNSE. It saves callers from needing to protect against PNSE.

Fix dotnet#90311

src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/ComWrappers.PlatformNotSupported.cs

@@ -11,12 +11,14 @@ public abstract partial class ComWrappers
     {
         public static unsafe bool TryGetComInstance(object obj, out IntPtr unknown)
         {
-            throw new PlatformNotSupportedException();
+            unknown = default;
+            return false;
         }
 
         public static unsafe bool TryGetObject(IntPtr unknown, [NotNullWhen(true)] out object? obj)
         {
-            throw new PlatformNotSupportedException();
+            obj = default;
+            return false;
         }
 
         public partial struct ComInterfaceDispatch