tests/tcg/ppc64le: add missing float reference file

Makefiles were skipping the output compare when such files
were not available. This results in arch being very inconsistent with
some providing all files, some providing no files, and some providing
some files. There was even one case of a misnamed file that result in a
skipped check.

For consistency, the current series adds all missing reference files for
all arch, and make their presence mandatory

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Aniket Sahu <asahu1x@linux.ibm.com>
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
Message-ID: <20260827221506.91574-78-pierrick.bouvier@oss.qualcomm.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>