bpftrace: remove RLIMIT_NOFILE workaround from nixos test

bpftrace 0.24 required more fd than previously for syscalls,
as we found out the hard way with test breaking.
Upstream rolled in an improvement setting ulimit automatically
and removing the need to adjust the test.

nixos/tests/bpf.nix

@@ -21,12 +21,7 @@
     # simple BEGIN probe (user probe on bpftrace itself)
     print(machine.succeed("bpftrace -e 'BEGIN { print(\"ok\\n\"); exit(); }'"))
     # tracepoint
-    # workaround: this needs more than the default of 1k FD to attach ~350 probes, bump fd limit
-    # see https://github.com/bpftrace/bpftrace/issues/2110
-    print(machine.succeed("""
-        ulimit -n 2048
-        bpftrace -e 'tracepoint:syscalls:sys_enter_* { print(probe); exit() }'
-    """))
+    print(machine.succeed("bpftrace -e 'tracepoint:syscalls:sys_enter_* { print(probe); exit() }'"))
     # kprobe
     print(machine.succeed("bpftrace -e 'kprobe:schedule { print(probe); exit() }'"))
     # BTF