[RELAY] Logging disabled for printing TVM IR


Prior to commit bfb4884, I was able to print the TVM IR for a Relay graph by setting the logging level to DEBUG. However, the aforementioned commit disabled that logging feature by commenting some lines in python/tvm/relay/backend/_backend.py and removing the logging import. It seems to be an inadvertent removal, so would it be possible to re-enable this?


Please feel free to send a PR to add the logging back.