selftests/bpf: Add hit/attach/detach race optimized uprobe test

selftests/bpf: Add hit/attach/detach race optimized uprobe test

Adding test that makes sure parallel execution of the uprobe and
attach/detach of optimized uprobe on it works properly.

By default the test runs for 500ms, which is adjustable by using
BPF_SELFTESTS_UPROBE_SYSCALL_RACE_MSEC env variable.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20250720112133.244369-16-jolsa@kernel.org