swift

13631900 - [test] Fix tests that use Swift include directory in unified builds (#78586)

[test] Fix tests that use Swift include directory in unified builds (#78586) In LLVM unified builds, Swift normally lives in `tools/swift` and the paths from the CMake build directory are not always the same as in a standalone build. Fix some tests using `%clang-include-dir` (which effectively points to `$CMAKE_BUILD_ROOT/include`) to use the new `%swift-include-dir`, which should point to the right `include/` directory in both unified and standalone builds. Additionally, change the calculation of `%clang-include-dir` to not be relative to the `swift` binary, but to the CMake build root instead.