Add RecordFunctionGuard (#36215)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/36215
Make it possible to disable observers, e.g. to avoid
infinite recursion if an observer uses an operator
Test Plan:
USE_BLAS=MKL USE_MKLDNN=0 USE_CUDA=0 python setup.py develop install
./build/bin/test_jit
Differential Revision: D20912676
Pulled By: ilia-cher
fbshipit-source-id: 29760cdfe488a02f943f755967b78779d6dbcef3
