COFF: Add back an assertion that is superseded by r222124

llvm-svn: 222735
diff --git a/llvm/lib/Object/COFFObjectFile.cpp b/llvm/lib/Object/COFFObjectFile.cpp
index d5ff7d6..04cd616 100644
--- a/llvm/lib/Object/COFFObjectFile.cpp
+++ b/llvm/lib/Object/COFFObjectFile.cpp
@@ -1060,7 +1060,7 @@
   else if (SymbolTable32)
     Ref.p = reinterpret_cast<uintptr_t>(SymbolTable32 + R->SymbolTableIndex);
   else
-    return symbol_end();
+    llvm_unreachable("no symbol table pointer!");
   return symbol_iterator(SymbolRef(Ref, this));
 }