Avoid fusion precompilation after ASV 0.3.0 is available

[kmaehashi]

(This is a reminder issue.)

Current code runs fuse precompilation for N^2 times (where N = number of def test_* benchmarks in bench_fuse) in one benchmark session (note that asv runs each benchmark in separate process). ASV 0.3.0 will introduce concept of warmup, so I'd like to use it.

cupy-benchmark/benchmarks/cupy/bench_fusion.py

Line 39 in 6a88619

fused_func(*args)