This PR addressed issue #140748 to support XRay instrumentation on the
host side when using offloading.
It makes the following changes:
- Initializes `XRayArgs` using the processed toolchain arguments instead
of the raw input.
- Removes the current caching mechanism of `XRayArgs` in the `ToolChain`
class, as this is error-prone and potential benefits are questionable.
For reference, `SanitizierArgs`, which is constructed in a similar
manner but is much more complex, does not use any caching.
- Adds driver tests to verify that XRay flags are set correctly with
offloading and `-Xarch_host`.
8d0a484983