Merge pull request #16734 from benlangmuir/san-split

[sourcekit test] Split -sanitizer= test out and add REQUIRES
diff --git a/lib/Markup/LineList.cpp b/lib/Markup/LineList.cpp
index 00b5de9..0afeb5e 100644
--- a/lib/Markup/LineList.cpp
+++ b/lib/Markup/LineList.cpp
@@ -25,7 +25,7 @@
     return "";
 
   auto FirstLine = Lines.begin();
-  while (FirstLine->Text.empty() && FirstLine != Lines.end())
+  while (FirstLine != Lines.end() && FirstLine->Text.empty())
     ++FirstLine;
 
   if (FirstLine == Lines.end())