Remove the last mention of LineTablesOnly from DwarfUnit, sinking it into DwarfCompileUnit

This is a useful distinction/invariant/delination to make because
LineTablesOnly mode is never relevant to type units, so it's clear that
we're not doing weird line-tables-only-with-types by making this API
choice.

It also lays the foundations nicely for adding gmlt-like data to fission
skeleton CUs while limiting the effects to CUs and not TUs.

llvm-svn: 221093
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index c691a2c..485ea34 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -832,7 +832,8 @@
                                                              DIE &SPDie) {
   DISubprogram SPDecl = SP.getFunctionDeclaration();
   DIScope Context = resolve(SPDecl ? SPDecl.getContext() : SP.getContext());
-  applySubprogramAttributes(SP, SPDie);
+  applySubprogramAttributes(SP, SPDie, getCUNode().getEmissionKind() ==
+                                           DIBuilder::LineTablesOnly);
   addGlobalName(SP.getName(), SPDie, Context);
 }
 } // end llvm namespace