clang-format: Consider operator precedence as penalty when breaking
before operators.

This fixes llvm.org/23382.

llvm-svn: 236602
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 9173061..cb1f7bd 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -3500,6 +3500,10 @@
       "             + cc;",
       Style);
 
+  verifyFormat("aaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
+               "    = aaaaaaaaaaaaaaaaaaaa + aaaaaaaaaaaaaaaaaaaaaaaaaaaa;",
+               Style);
+
   // Forced by comments.
   verifyFormat(
       "unsigned ContentSize =\n"