Fix bug in FlexiBLAS easyblock to allow AOCL-BLAS to be default

[lcniel]

In the current version, if one sets AOCL-BLAS as the default, it will be (silently) ignored and FlexiBLAS will use NETLIB instead, since the eventual name of the AOCL-BLAS backend will be the CMake name, AOCL_MT. This PR fixes this by substituting the name in configopts['FLEXIBLAS_DEFAULT'], just like how it's handled in the backends variable.

[boegel]

@boegelbot please test @ jsc-zen3
EB_BRANCH=5.0.x
EB_ARGS="FlexiBLAS-3.4.4-GCC-13.3.0.eb --installpath /tmp/$USER/pr3605"

[boegelbot]

@boegel: Request for testing this PR well received on jsczen3l1.int.jsc-zen3.fz-juelich.de

PR test command 'if [[ "5.0.x" != 'develop' ]]; then EB_BRANCH="5.0.x" ./easybuild_develop.sh 2> /dev/null 1>&2; EB_PREFIX=/home/boegelbot/easybuild/"5.0.x" source init_env_easybuild_develop.sh; fi; EB_PR=3605 EB_ARGS="FlexiBLAS-3.4.4-GCC-13.3.0.eb --installpath /tmp/$USER/pr3605" EB_REPO=easybuild-easyblocks EB_BRANCH="5.0.x" /opt/software/slurm/bin/sbatch --job-name test_PR_3605 --ntasks=8 ~/boegelbot/eb_from_pr_upload_jsc-zen3.sh' executed!

• exit code: 0
• output:

Submitted batch job 5788

Test results coming soon (I hope)...

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Message to humans: this is just bookkeeping information for me,
it is of no use to you (unless you think I have a bug, which I don't).

[boegelbot]

Test report by @boegelbot

Overview of tested easyconfigs (in order)

• SUCCESS FlexiBLAS-3.4.4-GCC-13.3.0.eb

Build succeeded for 1 out of 1 (1 easyconfigs in total)
jsczen3c1.int.jsc-zen3.fz-juelich.de - Linux Rocky Linux 9.5, x86_64, AMD EPYC-Milan Processor (zen3), Python 3.9.21
See https://gist.github.com/boegelbot/2364f4c511acc964d17feec48e7463c1 for a full test report.