[Clang][Driver] Fix the missing Target-Triple-Level include path resolution in Baremetal Driver (#165321)
The current baremetal driver implementation does not have a way to
derive the target-triple-level include path within the sysroot.
This feature is especially useful in setups where header paths deviate
from the default bare-metal assumptions. For example, when headers are
shared across target triples, it becomes necessary to organise them
under target-triple-specific directories to ensure correct resolution..