[C++] Substrait test fails in CI due to invalid path #47490
Description
Describe the bug, including details regarding any error messages, version, and platform.
As noted in #47455 (comment), the substrait test fails to properly read the PARQUET_TEST_DATA environment variable set in CI and parse it into a valid file path. It appears that the forward slashes are inadvertantly dropped
Component(s)
C++