contract engine slower than cp.einsum

[John-zzh]

Not sure when this behavior started, maybe just happened recently?

or maybe it is just warming up?

from gpu4pyscf.lib.cupy_helper import contract

import cupy as cp

from gpu4pyscf.lib import logger

logger.TIMER_LEVEL = 1
log = logger.new_logger(verbose=3)


eri3c = cp.random.rand(1234, 1234, 23).astype(cp.float32)
C_p = cp.random.rand(1234, 98).astype(cp.float32)

cpu1 = log.init_timer()
Ppq = cp.einsum('uvP,up->pvP', eri3c, C_p)
log.timer('cp.einsum', *cpu1)

cpu0 = log.init_timer()
Ppq = contract('uvP,up->pvP', eri3c, C_p)
log.timer('contract', *cpu0)

with the mkl-numpy environment from default channel 

CPU time for cp.einsum                                               0.08 sec, wall time      0.09 sec, GPU time     91.97 ms
CPU time for contract                                                0.24 sec, wall time      0.24 sec, GPU time    243.23 ms

[default_chanel.yml](https://github.com/user-attachments/files/24969977/default_chanel.yml)