Fix Memory leak in drm_memory_manager of OsHandleLinux

Add virtual deconstructor to OsHandle and deconstructor to OsHandleLinux
Add override keyword to destructor
Add overriding deconstructor to OsHandleWin
Add newline before private members

https://github.com/intel/compute-runtime/pull/550

Signed-off-by: Cameron S Murtagh <cameron.murtagh00@gmail.com>
Signed-off-by: Mateusz Jablonski <mateusz.jablonski@intel.com>

shared/source/memory_manager/host_ptr_defines.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2018-2021 Intel Corporation
+ * Copyright (C) 2018-2022 Intel Corporation
  *
  * SPDX-License-Identifier: MIT
  *
@@ -14,6 +14,8 @@
 namespace NEO {
 
 struct OsHandle {
+    virtual ~OsHandle() = default;
+
   protected:
     OsHandle() = default;
 };

shared/source/os_interface/linux/drm_allocation.h

@@ -18,6 +18,7 @@ enum class CachePolicy : uint32_t;
 enum class CacheRegion : uint16_t;
 
 struct OsHandleLinux : OsHandle {
+    ~OsHandleLinux() override = default;
     BufferObject *bo = nullptr;
 };
 

shared/source/os_interface/windows/wddm_allocation.h

@@ -15,6 +15,7 @@
 namespace NEO {
 
 struct OsHandleWin : OsHandle {
+    ~OsHandleWin() override = default;
     D3DKMT_HANDLE handle = 0;
     D3DGPU_VIRTUAL_ADDRESS gpuPtr = 0;
     Gmm *gmm = nullptr;