Encapsulate `LibretroHost` constructor

src/BizHawk.Emulation.Cores/Libretro/Libretro.cs

@@ -73,7 +73,21 @@ namespace BizHawk.Emulation.Cores.Libretro
 			}
 		}
 
+		/// <remarks>does not keep a reference to <paramref name="game"/></remarks>
 		public LibretroHost(CoreComm comm, IGameInfo game, string corePath, bool analysis = false)
+			: this(
+				comm,
+				libretroSystemDir: comm.CoreFileProvider.GetRetroSystemPath(game),
+				libretroSaveRAMDir: comm.CoreFileProvider.GetRetroSaveRAMDirectory(game),
+				corePath: corePath,
+				analysis: analysis) {}
+
+		public LibretroHost(
+			CoreComm comm,
+			string libretroSystemDir,
+			string libretroSaveRAMDir,
+			string corePath,
+			bool analysis)
 		{
 			try
 			{
@@ -95,11 +109,13 @@ namespace BizHawk.Emulation.Cores.Libretro
 					throw new InvalidOperationException("Unsupported Libretro API version (or major error in interop)");
 				}
 
-				bridge.LibretroBridge_SetDirectories(cbHandler,
+				var libretroCoreDir = Path.GetDirectoryName(corePath);
-					comm.CoreFileProvider.GetRetroSystemPath(game),
+				bridge.LibretroBridge_SetDirectories(
-					comm.CoreFileProvider.GetRetroSaveRAMDirectory(game),
+					cbHandler,
-					Path.GetDirectoryName(corePath),
+					systemDirectory: libretroSystemDir,
-					Path.GetDirectoryName(corePath));
+					saveDirectory: libretroSaveRAMDir,
+					coreDirectory: libretroCoreDir,
+					coreAssetsDirectory: libretroCoreDir);
 
 				ControllerDefinition = ControllerDef;
 				_notify = comm.Notify;