MdeModulePkg: Add DxeResetSystemLib unit test

https://bugzilla.tianocore.org/show_bug.cgi?id=2505

* Add unit test of DxeResetSystemLib library
  instance that uses cmocka interfaces to mock the
  UEFI Runtime Services Table and its ResetSystem()
  service.  When a unit test uses the cmocka
  interfaces, the unit test does not support being
  run from target environments.

  cmocka APIs: https://api.cmocka.org/index.html

  This example puts the unit test in a UnitTest
  directory below the library INF file and this location
  means the unit test is only designed to work this
  this one library instance.

* Add Test/MdeModulePkgHostTest.dsc to build host
  based unit tests

Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Bret Barkelew <Bret.Barkelew@microsoft.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Acked-by: Hao A Wu <hao.a.wu@intel.com>
Reviewed-by: Bret Barkelew <Bret.Barkelew@microsoft.com>

MdeModulePkg/Test/MdeModulePkgHostTest.dsc

@@ -0,0 +1,32 @@
+## @file
+# MdeModulePkg DSC file used to build host-based unit tests.
+#
+# Copyright (c) 2019 - 2020, Intel Corporation. All rights reserved.<BR>
+# Copyright (C) Microsoft Corporation.
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  PLATFORM_NAME           = MdeModulePkgHostTest
+  PLATFORM_GUID           = F74AF7C6-698C-4EBA-BA49-FF6816916354
+  PLATFORM_VERSION        = 0.1
+  DSC_SPECIFICATION       = 0x00010005
+  OUTPUT_DIRECTORY        = Build/MdeModulePkg/HostTest
+  SUPPORTED_ARCHITECTURES = IA32|X64
+  BUILD_TARGETS           = NOOPT
+  SKUID_IDENTIFIER        = DEFAULT
+
+!include UnitTestFrameworkPkg/UnitTestFrameworkPkgHost.dsc.inc
+
+[Components]
+  MdeModulePkg/Library/DxeResetSystemLib/UnitTest/MockUefiRuntimeServicesTableLib.inf
+
+  #
+  # Build MdeModulePkg HOST_APPLICATION Tests
+  #
+  MdeModulePkg/Library/DxeResetSystemLib/UnitTest/DxeResetSystemLibUnitTestHost.inf {
+    <LibraryClasses>
+      ResetSystemLib|MdeModulePkg/Library/DxeResetSystemLib/DxeResetSystemLib.inf
+      UefiRuntimeServicesTableLib|MdeModulePkg/Library/DxeResetSystemLib/UnitTest/MockUefiRuntimeServicesTableLib.inf
+  }