1. improve n-fold quantification algorithm by introducing a minimal size for each fold. 2. automatically search for best n for n-fold algorithm. (#2167)

* 1. add quantification_fold parameter. 2. support quantification test in run.py.

* implement n-fold quantification

* refine toolchain test=develop

* fix wrap compilation error

* fix yolov3 armv8 compilation test=develop

* revert to armv7 as default test=develop

* fix fpga compilation test=develop

* enable fast test compilation && push opencl kernels by run.py

* merge cl kernels into so

* restore pre-commit

* add slice cpu op

* print error var name && print op position

* prune faster depthwise

* fix style

* enhance scripts

* fix crash of tensor float * constructor

* fix fast check

* fix style

* support creating tensor with raw pointer.

* fix style

* fix fpga compilation error

* add auto debug tools

* fix style