Revert "DebugInfo: Omit class definitions even in the presence of available_externally vtables"

Patch crashing on a bootstrapping sanitizer bot:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/679

Reverting while I investigate.

This reverts commit r292768.

llvm-svn: 292801
diff --git a/clang/lib/CodeGen/CGVTables.cpp b/clang/lib/CodeGen/CGVTables.cpp
index 24c7f15..04c5cfe 100644
--- a/clang/lib/CodeGen/CGVTables.cpp
+++ b/clang/lib/CodeGen/CGVTables.cpp
@@ -744,10 +744,9 @@
     switch (keyFunction->getTemplateSpecializationKind()) {
       case TSK_Undeclared:
       case TSK_ExplicitSpecialization:
-        assert((def || CodeGenOpts.OptimizationLevel > 0 ||
-                CodeGenOpts.getDebugInfo() != codegenoptions::NoDebugInfo) &&
-               "Shouldn't query vtable linkage without key function, "
-               "optimizations, or debug info");
+        assert((def || CodeGenOpts.OptimizationLevel > 0) &&
+               "Shouldn't query vtable linkage without key function or "
+               "optimizations");
         if (!def && CodeGenOpts.OptimizationLevel > 0)
           return llvm::GlobalVariable::AvailableExternallyLinkage;