[luci/pass] Refactor FuseAddWithTConvPass

[jiwaszki]

This commit changes the order of searching for the pattern and adds tests for the pass.

ONE-DCO-1.0-Signed-off-by: Jan Iwaszkiewicz [email protected]

[jiwaszki]

For: #13685

@seanshpark some of my findings:

• As we discussed the checking of only one successor in [luci/pass] Introduce FuseMulWithFullyConnectedPass #13607 (comment) - it looks like the practice emerges in other passes as well.
  Here are the original lines from fuse_add_with_tconv:
  

  ONE/compiler/luci/pass/src/FuseAddWithTConvPass.cpp

  Lines 62 to 65 in 987fafa

  	// get add node
  	auto tconv_output = loco::succs(tconv);
  	assert(tconv_output.size() == 1);
  	auto add = dynamic_cast<luci::CircleAdd *>(*tconv_output.begin());

  
  I have decided not to change this check as the task is to refactor order of the search.
• There were no tests in FuseAddWithTConvPass.test.cpp besides name checking, so I have added them.

[jiwaszki]

@seanshpark @jinevening PR is ready to review. I cannot add you to reviewers or change the label (is it blocked for contributors?).

[seanshpark]

we don't need to do this change

[jiwaszki]

I wasn't sure about it as well... now I have guidance to follow. Will do!

[seanshpark]

ditto

[seanshpark]

LGTM thank you!