[SYCL][CMake] Honor LLVM_LIBDIR_SUFFIX (#22364) (#22417)
Cherry-pick of
https://github.com/intel/llvm/commit/acd7716ce2f09ba111e0d8769c28c372ad0c979d
LLVM CMake has the `LLVM_LIBDIR_SUFFIX` option to optionally add a
suffix to the install library directory, so setting
`-DLLVM_LIBDIR_SUFFIX=64` would result in a `lib64` library directory.
We didn't honor the variable correctly in `libdevice`, `xpti`, `xptifw`,
the driver, `sycl-jit` nor E2E testing.
This option will be set by Linux distros packing the repo, so we need it
to work.
After this, further work is required to get Driver `lit` tests to pass
with `LLVM_LIBDIR_SUFFIX` set, as the example device libraries we have
are always in `lib`.
Closes: https://github.com/intel/llvm/issues/22355
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Signed-off-by: Nick Sarnie <nick.sarnie@intel.com>
