[clang-format] Don't break between string literal operands of <<

Fixes #44363.

Author: owenca

clang/lib/Format/TokenAnnotator.cpp

@@ -5117,10 +5117,6 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
     return true;
   if (Left.IsUnterminatedLiteral)
     return true;
-  if (Right.is(tok::lessless) && Right.Next && Left.is(tok::string_literal) &&
-      Right.Next->is(tok::string_literal)) {
-    return true;
-  }
   if (Right.is(TT_RequiresClause)) {
     switch (Style.RequiresClausePosition) {
     case FormatStyle::RCPS_OwnLine:

clang/unittests/Format/FormatTest.cpp

@@ -26478,6 +26478,10 @@ TEST_F(FormatTest, PPBranchesInBracedInit) {
                "};");
 }
 
+TEST_F(FormatTest, StreamOutputOperator) {
+  verifyFormat("std::cout << \"foo\" << \"bar\" << baz;");
+}
+
 } // namespace
 } // namespace test
 } // namespace format