clang-format: Less eagerly try to keep label-value pairs on a line.

Before:
  string v =
      StrCat("aaaaaaaaaaaaaaaaaaaaaaaaaaa: ", SomeFunction(aaaaaaaaaaaa,
                                                           aaaaaaaaaaaaaaa),
             bbbbbbbbbbbbbbbbbbbbbbb);

After:
  string v = StrCat("aaaaaaaaaaaaaaaaaaaaaaaaaaa: ",
                    SomeFunction(aaaaaaaaaaaa, aaaaaaaaaaaaaaa),
                    bbbbbbbbbbbbbbbbbbbbbbb);

llvm-svn: 290337
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 09b8535..6f9df68 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -5220,6 +5220,10 @@
   verifyFormat("string v = StrCat(\"aaaaaaaaaaaa: \" +\n"
                "                  (aaaaaaa + aaaaa));",
                getLLVMStyleWithColumns(40));
+  verifyFormat(
+      "string v = StrCat(\"aaaaaaaaaaaaaaaaaaaaaaaaaaa: \",\n"
+      "                  SomeFunction(aaaaaaaaaaaa, aaaaaaaa.aaaaaaa),\n"
+      "                  bbbbbbbbbbbbbbbbbbbbbbb);");
 }
 
 TEST_F(FormatTest, UnderstandsEquals) {