Coverage: fix the missing output stream in recursive call to CoverageMappingContext::dump

llvm-svn: 214206
diff --git a/llvm/lib/ProfileData/CoverageMapping.cpp b/llvm/lib/ProfileData/CoverageMapping.cpp
index 30132a3..f9becdd 100644
--- a/llvm/lib/ProfileData/CoverageMapping.cpp
+++ b/llvm/lib/ProfileData/CoverageMapping.cpp
@@ -101,9 +101,9 @@
       return;
     const auto &E = Expressions[C.getExpressionID()];
     OS << '(';
-    dump(E.LHS);
+    dump(E.LHS, OS);
     OS << (E.Kind == CounterExpression::Subtract ? " - " : " + ");
-    dump(E.RHS);
+    dump(E.RHS, OS);
     OS << ')';
     break;
   }