[clang] [Clang][BPF] Add __BPF_FEATURE_GOTOX (PR #165456)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-aarch64-quick` running on `linaro-clang-aarch64-quick` while building `clang` at step 5 "ninja check 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/65/builds/24645

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (ninja check 1) failure: stage 1 checked (failure)
******************** TEST 'Clangd Unit Tests :: ./ClangdTests/160/335' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/tools/clang/tools/extra/clangd/unittests/./ClangdTests-Clangd Unit Tests-1415516-160-335.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=335 GTEST_SHARD_INDEX=160 /home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/tools/clang/tools/extra/clangd/unittests/./ClangdTests
--

Note: This is test shard 161 of 335.
[==========] Running 4 tests from 4 test suites.
[----------] Global test environment set-up.
[----------] 1 test from CompletionTest
[ RUN      ] CompletionTest.InsertIncludeOrImport
Built preamble of size 707732 for file /clangd-test/foo.cpp version null in 0.41 seconds
Code complete: fuzzyFind({
  "AnyScope": false,
  "Limit": null,
  "PreferredTypes": [],
  "ProximityPaths": [
    "/clangd-test/foo.cpp"
  ],
  "Query": "Fun",
  "RestrictForCodeCompletion": true,
  "Scopes": [
    ""
  ]
})
Code complete: sema context TopLevel, query scopes [] (AnyScope=false), expected type <none>
Code complete: 0 results from Sema, 1 from Index, 0 matched, 0 from identifiers, 1 returned.
Built preamble of size 709276 for file /clangd-test/Foo.m version null in 0.52 seconds
Code complete: fuzzyFind({
  "AnyScope": false,
  "Limit": null,
  "PreferredTypes": [],
  "ProximityPaths": [
    "/clangd-test/Foo.m"
  ],
  "Query": "Fun",
  "RestrictForCodeCompletion": true,
  "Scopes": [
    ""
  ]
})
Code complete: sema context TopLevel, query scopes [] (AnyScope=false), expected type <none>
Code complete: 0 results from Sema, 1 from Index, 0 matched, 0 from identifiers, 1 returned.
Built preamble of size 707732 for file /clangd-test/foo.cpp version null in 0.17 seconds
Code complete: fuzzyFind({
  "AnyScope": false,
  "Limit": null,
  "PreferredTypes": [],
  "ProximityPaths": [
    "/clangd-test/foo.cpp"
...

```

</details>

https://github.com/llvm/llvm-project/pull/165456