selftests/bpf: Use explicit bpf_prog_test_load() calls everywhere

-Dbpf_prog_load_deprecated=bpf_prog_test_load trick is both ugly and
breaks when deprecation goes into effect due to macro magic. Convert all
the uses to explicit bpf_prog_test_load() calls which avoid deprecation
errors and makes everything less magical.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20211103220845.2676888-12-andrii@kernel.org

tools/testing/selftests/bpf/test_tcpnotify_user.c

@@ -25,6 +25,7 @@
 
 #include "test_tcpnotify.h"
 #include "trace_helpers.h"
+#include "testing_helpers.h"
 
 #define SOCKET_BUFFER_SIZE (getpagesize() < 8192L ? getpagesize() : 8192L)
 
@@ -92,7 +93,7 @@ int main(int argc, char **argv)
 	if (cg_fd < 0)
 		goto err;
 
-	if (bpf_prog_load(file, BPF_PROG_TYPE_SOCK_OPS, &obj, &prog_fd)) {
+	if (bpf_prog_test_load(file, BPF_PROG_TYPE_SOCK_OPS, &obj, &prog_fd)) {
 		printf("FAILED: load_bpf_file failed for: %s\n", file);
 		goto err;
 	}