Add dummy symbols for Swift runtime unit tests

Author: DougGregor

unittests/runtime/Stdlib.cpp

@@ -520,3 +520,11 @@ const long long $ss7KeyPathCMo[1] = {0};
 
 SWIFT_RUNTIME_STDLIB_INTERNAL
 const long long $ss12__SwiftValueCMn[1] = {0};
+
+// Never and Error
+
+SWIFT_RUNTIME_STDLIB_INTERNAL
+const long long $ss5NeverOMn[1] = {0};
+
+SWIFT_RUNTIME_STDLIB_INTERNAL
+const long long $ss5ErrorMp[1] = {0};