[SYCL][E2E] Fix Win path handling in lit config (#18135)
Fixes consequence of
https://github.com/intel/llvm/commit/4150bdff5eaae27d5b99ad46042412cd39ad8fa1
f'"{path}"' converts empty string to the string with quotes and length
== 2 that breaks checks for not empty path. Fixes that.
Signed-off-by: Tikhomirova, Kseniya <kseniya.tikhomirova@intel.com>
