tests: Rename some test files in cputestdata

tests: Rename some test files in cputestdata

The files contained the "-invalid" marker in their filename, marking
them as test cases that are supposed to fail in the virschematest.
Unfortunately, the "-invalid" marker does not discriminate between
different tests the files might be used in.

A later patch will introduce a new test validating the XML. This
test is not supposed to fail, as the files contain valid XML.

Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>