[clang] [clang-repl] Set up native platform support if ORC Runtime available (PR #217988)

[via cfe-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Windows-->
# :window: Windows x64 Test Results

* 56258 tests passed
* 1532 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### Clang-Unit
<details>
<summary>Clang-Unit.Interpreter/_/ClangReplInterpreterTests_exe/InterpreterTest/NativePlatformSupport</summary>

```
Script:
--
C:\_work\llvm-project\llvm-project\build\tools\clang\unittests\Interpreter\.\ClangReplInterpreterTests.exe --gtest_filter=InterpreterTest.NativePlatformSupport
--
unknown file
SEH exception with code 0x3221225501 thrown in the test body.
Stack trace:



```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/217988