CMP0141: Fix PCH REUSE_FROM when MSVC_DEBUG_INFORMATION_FORMAT is empty

Under the policy's NEW behavior, `[CMAKE_]MSVC_DEBUG_INFORMATION_FORMAT`
may be explicitly set to an empty string to tell CMake not to add any
flags for this abstraction.  In this case, fall back to checking the
language-wide flags as we do in the OLD behavior.

This revises commit 183b9a9eca (CMP0141: Fix PCH REUSE_FROM under policy
NEW behavior, 2022-10-31, v3.25.0-rc3~4^2).

Issue: #24106