ci: Enable benchmarks on Aarch64

[tgross35]

This was originally attempted at 1, but the numbers seemed to indicate that tests weren't being run or counted completely. That issue appears to be resolved, so add benchmarks for Aarch64.

[tgross35]

Whatever the issue in #930 (comment) was seems to be resolved.

icount::icount_bench_acos_group::icount_bench_acos logspace:setup_acos()
  Baselines:                      softfloat|softfloat (old)
  Instructions:                       14259|N/A                  (*********)
  L1 Hits:                            17574|N/A                  (*********)
  LL Hits:                                2|N/A                  (*********)
  RAM Hits:                              23|N/A                  (*********)
  Total read+write:                   17599|N/A                  (*********)
  Estimated Cycles:                   18389|N/A                  (*********)

From a quick skim, everything seems to be within an order of magnitude of x86.