kernel/process: move current process to kernel instance

Two functional change:
QueryProcessMemory uses the process passed from handle instead current_process
Thread::Stop() uses TLS from owner_process instead of current_process

src/core/hle/kernel/handle_table.cpp

@@ -5,6 +5,7 @@
 #include <utility>
 #include "common/assert.h"
 #include "common/logging/log.h"
+#include "core/core.h" // TODO: for current_process. Remove this later
 #include "core/hle/kernel/errors.h"
 #include "core/hle/kernel/handle_table.h"
 #include "core/hle/kernel/process.h"
@@ -76,7 +77,9 @@ SharedPtr<Object> HandleTable::GetGeneric(Handle handle) const {
     if (handle == CurrentThread) {
         return GetCurrentThread();
     } else if (handle == CurrentProcess) {
-        return g_current_process;
+        // TODO: should this return HandleTable's parent process, or kernel's current process?
+        // Should change this either way
+        return Core::System::GetInstance().Kernel().GetCurrentProcess();
     }
 
     if (!IsValid(handle)) {