Get rid of a redundant argument DOWNSTREAM from VisiblePosition constructor call sites

Source/core/editing/iterators/TextIterator.cpp

Index: Source/core/editing/iterators/TextIterator.cpp
diff --git a/Source/core/editing/iterators/TextIterator.cpp b/Source/core/editing/iterators/TextIterator.cpp
index df66d1a9530393d71fb26e65fe9cbc13c8bcb6bb..b1c57bc7f7e2f8453306112f343dcf4b131232b2 100644
--- a/Source/core/editing/iterators/TextIterator.cpp
+++ b/Source/core/editing/iterators/TextIterator.cpp
@@ -876,8 +876,8 @@ bool TextIteratorAlgorithm<Strategy>::shouldRepresentNodeOffsetZero()
     // and in that case we'll get null. We don't want to put in newlines at the start in that case.
     // The currPos.isNotNull() check is needed because positions in non-HTML content
     // (like SVG) do not have visible positions, and we don't want to emit for them either.
-    VisiblePosition startPos = VisiblePosition(Position(m_startContainer, m_startOffset), DOWNSTREAM);
-    VisiblePosition currPos = VisiblePosition(positionBeforeNode(m_node), DOWNSTREAM);
+    VisiblePosition startPos = VisiblePosition(Position(m_startContainer, m_startOffset));
+    VisiblePosition currPos = VisiblePosition(positionBeforeNode(m_node));
     return startPos.isNotNull() && currPos.isNotNull() && !inSameLine(startPos, currPos);
 }