2) Update the file and function header comments in the BasePeCoffExtraActionLibNull
3) Add ASSERT() statements to APIs in BasePeCoffExtraActionLibNull is ImageContext is NULL.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@8272 6f19259b-4bc3-4df7-8a09-765794883524