selftests: mm: make map_fixed_noreplace test names stable

KTAP parsers interpret the output of ksft_test_result_*() as being the
name of the test.  The map_fixed_noreplace test uses a dynamically
allocated base address for the mmap()s that it tests and currently
includes this in the test names that it logs so the test names that are
logged are not stable between runs.  It also uses multiples of PAGE_SIZE
which mean that runs for kernels with different PAGE_SIZE configurations
can't be directly compared.  Both these factors cause issues for CI
systems when interpreting and displaying results.

Fix this by replacing the current test names with fixed strings describing
the intent of the mappings that are logged, the existing messages with the
actual addresses and sizes are retained as diagnostic prints to aid in
debugging.

Link: https://lkml.kernel.org/r/20240605-kselftest-mm-fixed-noreplace-v1-1-a235db8b9be9@kernel.org


Fixes: 4838cf70 ("selftests/mm: map_fixed_noreplace: conform test to TAP format output")
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>