add unit test for Bk2 IsStv mode

Author: adelikat

tests/TASVideos.MovieParsers.Tests/Bk2ParserTests.cs

@@ -85,6 +85,7 @@ public async Task PalFlag_True(string fileName, RegionType expected)
 	[DataRow("System-A7800.bk2", SystemCodes.Atari7800)]
 	[DataRow("System-AppleII.bk2", SystemCodes.AppleII)]
 	[DataRow("System-Arcade.bk2", SystemCodes.Arcade)]
+	[DataRow("System-Arcade-IsStv.bk2", SystemCodes.Arcade)]
 	[DataRow("System-Bsx.bk2", SystemCodes.Bsx)]
 	[DataRow("System-C64.bk2", SystemCodes.C64)]
 	[DataRow("System-Intellivision.bk2", SystemCodes.Intellivision)]