[ELF] Revert "Also demote lazy symbols."

This reverts commit https://reviews.llvm.org/rL330869
for a regression to link Android dex2oatds.

Differential Revision: https://reviews.llvm.org/D51892

llvm-svn: 342007
diff --git a/lld/ELF/Symbols.cpp b/lld/ELF/Symbols.cpp
index c16bda8..d007e44 100644
--- a/lld/ELF/Symbols.cpp
+++ b/lld/ELF/Symbols.cpp
@@ -103,7 +103,8 @@
     return 0;
   case Symbol::LazyArchiveKind:
   case Symbol::LazyObjectKind:
-    llvm_unreachable("lazy symbol reached writer");
+    assert(Sym.IsUsedInRegularObj && "lazy symbol reached writer");
+    return 0;
   }
   llvm_unreachable("invalid symbol kind");
 }