Migrate to .NET 9 (#198)

src/Ryujinx.Memory/Ryujinx.Memory.csproj

@@ -1,7 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <DefaultItemExcludes>$(DefaultItemExcludes);._*</DefaultItemExcludes>
   </PropertyGroup>

src/Ryujinx.Memory/SparseMemoryBlock.cs

@@ -14,7 +14,7 @@ namespace Ryujinx.Memory
 
         private readonly PageInitDelegate _pageInit;
 
-        private readonly object _lock = new object();
+        private readonly Lock _lock = new();
         private readonly ulong _pageSize;
         private readonly MemoryBlock _reservedBlock;
         private readonly List<MemoryBlock> _mappedBlocks;

src/Ryujinx.Memory/Tracking/RegionHandle.cs

@@ -51,7 +51,7 @@ namespace Ryujinx.Memory.Tracking
 
         private event Action OnDirty;
 
-        private readonly object _preActionLock = new();
+        private readonly Lock _preActionLock = new();
         private RegionSignal _preAction; // Action to perform before a read or write. This will block the memory access.
         private PreciseRegionSignal _preciseAction; // Action to perform on a precise read or write.
         private readonly List<VirtualRegion> _regions;