[libcxx] Fix include paths in fuzzing/partial_sort.pass.cpp

[miyuki]

Summary

When testing an installed (out-of-tree) version of libc++, the
"libcxx/fuzzing/partial_sort.pass.cpp" test fails because of missing
include files "../fuzzing/fuzzing.{h,cpp}". This happens because in
the source tree "../fuzzing" can be accessed as
"libcxx/include/../fuzzing", but with the installed library this does
not work.

This patch fixes the issue by changing the path to be relative from
the `libcxx/test/fuzzing" directory.

[merge_guards_bot]

Unit tests: pass. 60837 tests passed, 0 failed and 726 were skipped.

clang-format: fail. Please format your changes with clang-format by running git-clang-format HEAD^ or apply this patch.

Build artifacts: console-log.txt, CMakeCache.txt, clang-format.patch, test-results.xml, diff.json

[mclow.lists]

Please don't commit to libc++ w/o approval from one of the "approvers": @mclow.lists, @EricWF or @ldionne .

@michaelplatings, please don't approve libc++ patches.
I appreciate the reviews, and you should give feedback, but please don't approve (say LGTM instead).

Does this change break OSS-Fuzz? Did anyone try?

[miyuki]

Does this change break OSS-Fuzz? Did anyone try?

I did not know that these tests are supposed to interact with an external component. Sorry about that. I'll wait for approval from the libc++ approvers in my future patches.

libcxx/test/libcxx/fuzzing/partial_sort.pass.cpp

 // -*- C++ -*-
 //===-------------------------- partial_sort.cpp --------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++98, c++03
 
 #include <cassert>
 #include <cstring> // for strlen
 
-#include "../fuzzing/fuzzing.h"
-#include "../fuzzing/fuzzing.cpp"
+#include "../../../fuzzing/fuzzing.h"
+#include "../../../fuzzing/fuzzing.cpp"
 
 const char* test_cases[] = {"", "s", "bac",
                             "bacasf"
                             "lkajseravea",
                             "adsfkajdsfjkas;lnc441324513,34535r34525234"};
 
 const size_t k_num_tests = sizeof(test_cases) / sizeof(test_cases[0]);
 
 int main(int, char**) {
   for (size_t i = 0; i < k_num_tests; ++i) {
     const size_t size = std::strlen(test_cases[i]);
     const uint8_t* data = (const uint8_t*)test_cases[i];
     assert(0 == fuzzing::partial_sort(data, size));
   }
   return 0;
 }