[clang-format] add a regression test for include sorting

[krasimir]

Summary

This adds a regression test from the comments
on https://reviews.llvm.org/D121370.

[krasimir]

• update with just the last commit

clang/unittests/Format/SortIncludesTest.cpp

EXPECT_EQ("#include \"a.h\"\n"
             "#include \"b.h\"\n"
             "#include \"c.h\"\n",
             sort("#include \"a.h\"\n"
                  "#include \\\n"
                  "\"c.h\"\n"
                  "#include \"b.h\"\n"));
 }
 
+TEST_F(SortIncludesTest, HandlesTrailingCommentsWithAngleBrackets) {
+  // Regression test from the discussion at https://reviews.llvm.org/D121370.
+  EXPECT_EQ("#include <cstdint>\n"
+            "\n"
+            "#include \"util/bar.h\"\n"
+            "#include \"util/foo/foo.h\" // foo<T>\n",
+            sort("#include <cstdint>\n"
+                 "\n"
+                 "#include \"util/bar.h\"\n"
+                 "#include \"util/foo/foo.h\" // foo<T>\n",
+                 /*FileName=*/"input.cc",
+                 /*ExpectedNumRanges=*/0));
+}
+
 TEST_F(SortIncludesTest, LeavesMainHeaderFirst) {
   Style.IncludeIsMainRegex = "([-_](test|unittest))?$";
   EXPECT_EQ("#include \"llvm/a.h\"\n"
             "#include \"b.h\"\n"
             "#include \"c.h\"\n",
             sort("#include \"llvm/a.h\"\n"
                  "#include \"c.h\"\n"
                  "#include \"b.h\"\n",