selftests/bpf: enable many-args tests for arm64

Now that support for up to 12 args is enabled for tracing programs on
ARM64, enable the existing tests for this feature on this architecture.

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Link: https://lore.kernel.org/r/20250527-many_args_arm64-v3-2-3faf7bb8e4a2@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Author: Tropicao

tools/testing/selftests/bpf/DENYLIST.aarch64

@@ -1,3 +1 @@
-fentry_test/fentry_many_args                     # fentry_many_args:FAIL:fentry_many_args_attach unexpected error: -524
-fexit_test/fexit_many_args                       # fexit_many_args:FAIL:fexit_many_args_attach unexpected error: -524
 tracing_struct/struct_many_args                  # struct_many_args:FAIL:tracing_struct_many_args__attach unexpected error: -524