For kernels that have removed the section-aligned namespace constraint
validate that multiple namespaces can be created / deleted that collide
within a given section.

While this test acts on the ACPI.NFIT bus it is not marked "destructive"
because it only operates in available capacity and marks each namespace
created with a unique volume name ("subsection-test").

Signed-off-by: Dan Williams <dan.j.williams@intel.com>