[ELF] Test rejected --detect-odr-violations

Author: MaskRay

lld/test/ELF/silent-ignore.test

@@ -19,3 +19,11 @@ RUN:   -EB \
 RUN:   -EL \
 RUN:   -G 0
 RUN: not ld.lld --version --not-an-ignored-argument
+
+Test some options that we reject (including those what we used to silently ignore).
+
+--detect-odr-violations is a gold-specific option that we don't implement and if
+we do, probably in a different way under a different spelling.
+RUN: not ld.lld --detect-odr-violations 2>&1 | FileCheck %s
+
+CHECK: error: unknown argument