[3.13] gh-120418: Don't assume wheeldata is deleted if `WHEEL_PKG_DIR` is set (GH...

[3.13] gh-120418: Don't assume wheeldata is deleted if `WHEEL_PKG_DIR` is set (GH-120419) (#120432)

gh-120418: Don't assume wheeldata is deleted if `WHEEL_PKG_DIR` is set (GH-120419)

Remove wheeldata from both sides of the `assertEqual`, so that we're
*actually* ignoring it from the test set.

This test is only making assertions about the source tree, no code is
being executed that would do anything different based on the value of
`WHEEL_PKG_DIR`.
(cherry picked from commit 030b452e34bbb0096acacb70a31915b9590c8186)

Co-authored-by: Stefano Rivera <stefano@rivera.za.net>