clang-format: Improve address-of-operator detection

Before:
  size = sizeof * a;

After:
  size = sizeof *a;

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191139 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index fc13ad1..a113682 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -3851,6 +3851,7 @@
   verifyIndependentOfContext("if (*b[i])");
   verifyIndependentOfContext("if (int *a = (&b))");
   verifyIndependentOfContext("while (int *a = &b)");
+  verifyIndependentOfContext("size = sizeof *a;");
   verifyFormat("void f() {\n"
                "  for (const int &v : Values) {\n"
                "  }\n"