Fix NCE Destruction

NCE is implicitly depended on by the `GPU` class due to the NCE Memory Trapping API so the destruction of it must take place after the destruction of the `GPU` class. Additionally, to prevent bugs the NCE destructor must set `staticNce` to `nullptr` as the signal handler will potentially access a destroyed instance of NCE otherwise.

app/src/main/cpp/skyline/common.h

@@ -63,13 +63,13 @@ namespace skyline {
         std::shared_ptr<JvmManager> jvm;
         std::shared_ptr<Settings> settings;
         std::shared_ptr<loader::Loader> loader;
+        std::shared_ptr<nce::NCE> nce;
         std::shared_ptr<kernel::type::KProcess> process{};
         static thread_local inline std::shared_ptr<kernel::type::KThread> thread{}; //!< The KThread of the thread which accesses this object
         static thread_local inline nce::ThreadContext *ctx{}; //!< The context of the guest thread for the corresponding host thread
         std::shared_ptr<gpu::GPU> gpu;
         std::shared_ptr<soc::SOC> soc;
         std::shared_ptr<audio::Audio> audio;
-        std::shared_ptr<nce::NCE> nce;
         std::shared_ptr<kernel::Scheduler> scheduler;
         std::shared_ptr<input::Input> input;
     };

app/src/main/cpp/skyline/nce.cpp

@@ -118,7 +118,7 @@ namespace skyline::nce {
         }
     }
 
-    static NCE* staticNce{nullptr}; //!< A static instance of NCE for use in the signal handler
+    static NCE *staticNce{nullptr}; //!< A static instance of NCE for use in the signal handler
 
     void NCE::HostSignalHandler(int signal, siginfo *info, ucontext *ctx) {
         if (signal == SIGSEGV) {
@@ -168,6 +168,10 @@ namespace skyline::nce {
         staticNce = this;
     }
 
+    NCE::~NCE() {
+        staticNce = nullptr;
+    }
+
     constexpr u8 MainSvcTrampolineSize{17}; // Size of the main SVC trampoline function in u32 units
     constexpr u32 TpidrEl0{0x5E82};         // ID of TPIDR_EL0 in MRS
     constexpr u32 TpidrroEl0{0x5E83};       // ID of TPIDRRO_EL0 in MRS

app/src/main/cpp/skyline/nce.h

@@ -75,6 +75,8 @@ namespace skyline::nce {
          */
         NCE(const DeviceState &state);
 
+        ~NCE();
+
         struct PatchData {
             size_t size; //!< Size of the .patch section
             std::vector<size_t> offsets; //!< Offsets in .text of instructions that need to be patched