clang-format: Fix regression introduced by r189337.

Before:
  if (aaaaaaaaaaaaaaaaaaaaaaaaaa.aaaaaaaaaaaaaaaaaaaaaa(
          aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) == 5) ...

After:
  if (aaaaaaaaaaaaaaaaaaaaaaaaaa.aaaaaaaaaaaaaaaaaaaaaa(
          aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)
      == 5) ...

Also precompute startsBinaryExpression() to improve performance.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@190124 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 3eaa69a..6e9516d 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -2341,6 +2341,10 @@
       "if (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(\n"
       "        aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) == 5) {\n"
       "}");
+  verifyFormat(
+      "if (aaaaaaaaaaaaaaaaaaaaaaaaaa.aaaaaaaaaaaaaaaaaaaaaa(\n"
+      "        aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) == 5) {\n"
+      "}");
   // Even explicit parentheses stress the precedence enough to make the
   // additional break unnecessary.
   verifyFormat(