Investigate BF16 Integration tests on Arm

[rengolin]

Now that we're adding a new Arm builder (with benchmarks), we should make sure that our BF16 tests work on that platform. The tests are under test/BF16/Integration which has a restriction that they're only checked on x86 platforms. We need to change that.

One of the errors was found in #1020:
error: 'xsmm.brgemm.dispatch' op expect lda to be >= of dimension k