test/multicqes_drain: reset multi_cap between test_generic_drain calls

multi_cap is a global that caps the number of multishot SQEs per run.
It gets decremented during SQE generation but was never reset between
iterations, so calls 2-5 of test_generic_drain() could not generate any
multishot SQEs (multi_cap <= 0 makes retry1 always true). With no
multishot SQEs, cancel ops are also excluded (cnt stays 0), leaving
only single and nop ops for those iterations.

Reset multi_cap at the start of each call.

Signed-off-by: Sebastian Chlad <sebastian.chlad@suse.com>

Author: schlad

test/multicqes_drain.c

@@ -189,6 +189,7 @@ static int test_generic_drain(struct io_uring *ring)
 	int i, j, ret, arg = 0;
 	int pipes[max_entry][2];
 	int pre_flags = 0;
+	multi_cap = max_entry / 5;
 
 	for (i = 0; i < max_entry; i++) {
 		if (pipe(pipes[i]) != 0) {