MdeModulePkg: Add NULL pointer check for RegularExpressionDxe.

Refine code by adding NULL pointer check to avoid potential NULL pointer dereferenced.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Qiu Shumin <shumin.qiu@intel.com>
Reviewed-by: Samer El-Haj-Mahmoud <elhaj@hpe.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19271 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Universal/RegularExpressionDxe/RegularExpressionDxe.c

@@ -130,6 +130,10 @@ OnigurumaMatch (
   //
   Start = (OnigUChar*)String;
   Region = onig_region_new ();
+  if (Region == NULL) {
+    onig_free (OnigRegex);
+    return EFI_OUT_OF_RESOURCES;
+  }
   OnigResult = onig_search (
                  OnigRegex,
                  Start,