[CI] typo fix: is_hip --> is_hip()

[youkaichao]

Fix a typo in function call

[youkaichao]

hhh funny things happened, NUM_BLOCKS = [1024, 36000] not only breaks rocm but also breaks cuda, but we used to only test with NUM_BLOCKS = [1024, 10000] because not is_hip is always False (is_hip is a function).

[zhuohan123]

LGTM! Thanks for the fix! I guess the test failure is due to L4's limited memory size?

[youkaichao]

Our test is run in L4 machine, and previous test succeeded because they use [1024, 10000]. We never tested [1024, 36000] because not is_hip is always False, or is_hip is always True.