Fix memory leak that the rpmalloc assert warns of (#5776) (Fixes #5733)

Hack to take care of the assertion sent by the rpmalloc memory manager. Creates a static "free" function for NotePlayHandleManager and then shoves it right before the program ends.

Co-authored-by: Pause for Affliction <47124830+Epsilon-13@users.noreply.github.com>

include/NotePlayHandle.h

@@ -349,6 +349,7 @@ public:
 					NotePlayHandle::Origin origin = NotePlayHandle::OriginPattern );
 	static void release( NotePlayHandle * nph );
 	static void extend( int i );
+	static void free();
 
 private:
 	static NotePlayHandle ** s_available;

src/core/NotePlayHandle.cpp

@@ -623,3 +623,8 @@ void NotePlayHandleManager::extend( int c )
 		++n;
 	}
 }
+
+void NotePlayHandleManager::free()
+{
+	MM_FREE(s_available);
+}

src/core/main.cpp

@@ -1009,5 +1009,8 @@ int main( int argc, char * * argv )
 	}
 #endif
 
+
+	NotePlayHandleManager::free();
+
 	return ret;
 }