Improve bgemm and sbgemm testing

- Fixes wrong return type for `is_close`
- Adds stricter compiler flags for test files so we don't see the above
issue again
- Re-uses test helper functions between compare_sgemm_sbgemm/bgemm.c

Fix compilation of the new bgemm test

Add optimized BGEMM kernel for NEOVERSEV1 target

This also improves the testing and generic kernel by re-using the BF16
conversion functions.

Built on top of https://github.com/OpenMathLib/OpenBLAS/pull/5357 and derived from https://github.com/OpenMathLib/OpenBLAS/pull/5287

Co-authored-by: Ye Tao <ye.tao@arm.com>

Complete the infrastructure changes for adding BGEMM

Fix workspace allocation in LAPACKE strsen/dtrsen (Reference-LAPACK PR 1144)

Temporarily disable test_bgemm

Fix arm64 HAVE_SME setting for DYNAMIC_ARCH builds using CMake

Add infrastructure for BGEMM

Optimize gemv_n_sve_v1x3 kernel

This fixes the build and tests on `NEOVERSEV1` target, which was failing
with specific constants for `SBGEMM`

Co-authored-by: Ye Tao <ye.tao@arm.com>

Setting up all the infrastructure for BGEMM support in OpenBLAS, hopefully I found all the right places.

Derived mostly from the previous work done in https://github.com/OpenMathLib/OpenBLAS/pull/5287

Co-authored-by: Ye Tao <ye.tao@arm.com>

change BLAS_HALF to BLAS_BFLOAT16 in parallelized POTRF (another missed rename)

Fix SBGEMM BFLOAT16 build

Add Support for POWER11

Update CONTRIBUTORS.md

Fix cpuid.S on arm

The ARM assembly syntax differs a bit

Fixes 61b9339d3a getarch/cpuid.S: Fix warning about executable stack

Signed-off-by: Sertonix <sertonix@posteo.net>

update gitignore configuration

Update README.md to include Windows on Arm64

Performance improvements of [SD]DOT with loop-unrolling on A64FX

Update README.md to indicate that binaries are available for Windows on ARM64

Improve [SD]SYEVD performance by parallelizing [SD]LAED3

Multi-thread Performance Improvement of GEMM with DIVIDE_RATE=1 for A64FX

A64FX.

Exit if memory allocation keeps failing, instead of retrying forever

Declare the server_lock mutex volatile in addition to static

Fix documentation error and ordering bug in ?LAED/?LASD  (Reference-LAPACK PR 1140)