MdeModulePkg/UefiSortLib:Add UefiSortLib unit test

Adding two unit test case for UefiSortLib. One is a test on
sorting an array of UINT32 by using PerformQuickSort, another
is a test on comparing the same buffer by using StringCompare.
Add 'main' function name to ECC exception list to avoid ECC
error.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Signed-off-by: Wenyi Xie <xiewenyi2@huawei.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>

MdeModulePkg/Test/MdeModulePkgHostTest.dsc

@@ -41,3 +41,9 @@
     <PcdsFixedAtBuild>
       gEfiMdeModulePkgTokenSpaceGuid.PcdAllowVariablePolicyEnforcementDisable|TRUE
   }
+
+  MdeModulePkg/Library/UefiSortLib/UnitTest/UefiSortLibUnitTest.inf {
+    <LibraryClasses>
+      UefiSortLib|MdeModulePkg/Library/UefiSortLib/UefiSortLib.inf
+      DevicePathLib|MdePkg/Library/UefiDevicePathLib/UefiDevicePathLib.inf
+  }