MdeModulePkg: Change complex DEBUG_CODE() to DEBUG_CODE_BEGIN/END()

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3767

Update use of DEBUG_CODE(Expression) if Expression is a complex code
block with if/while/for/case statements that use {}.

Cc: Andrew Fish <afish@apple.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Michael Kubacki <michael.kubacki@microsoft.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>

MdeModulePkg/Library/UefiBootManagerLib/BmBoot.c

@@ -1387,7 +1387,7 @@ BmExpandLoadFile (
   //
   FileBuffer = AllocateReservedPages (EFI_SIZE_TO_PAGES (BufferSize));
   if (FileBuffer == NULL) {
-    DEBUG_CODE (
+    DEBUG_CODE_BEGIN ();
       EFI_DEVICE_PATH *LoadFilePath;
       CHAR16          *LoadFileText;
       CHAR16          *FileText;
@@ -1417,7 +1417,7 @@ BmExpandLoadFile (
       if (LoadFileText != NULL) {
         FreePool (LoadFileText);
       }
-      );
+    DEBUG_CODE_END ();
     return NULL;
   }