Update to TVM v0.6

Updates our TVM code from v0.4 to v0.6. Tidies up some of the TVM dependency code too, but not all of it.

This is a "big" change, but it shouldn't break anything major. The main changes are in the compilation process from TVM models to Clockwork models; our Clockwork runtime only had a couple of changes, the tests all pass, and if anything breaks it'll be easy to track down the root cause.

@salzayat @rkarimi once this commit is merged, it will break your current environments. You'll need to pay attention to two things:

1. Updating your TVM checkout
2. Making sure you're using the correct model repository (if you're using one)

More specifically:

• Concurrent with this change, I will merge changes to the tvm repository. You will need to pull those changes and rebuild TVM. This updates us to v0.6.
• There's been a small tweak to our model format. Previously compiled models won't work without recompiling them. If you need this, talk to me; but I assume you aren't using any custom/personal models.
• The out-of-the-box models in clockwork/resources have been updated and will work fine. If these are the only models you've been using, then you don't need to change anything.
• Models in the clockwork-modelzoo-volta repository have been updated and will continue to work
• Models in tvm-modelzoo no longer work, if you have been using those.

bin/convert.py

@@ -9,6 +9,9 @@ Clockwork must be build in order to run this script.
 This script uses the `convert` binary and expects it to exist in the `build` folder
 """
 
+convert_exec = os.path.join(os.path.dirname(os.path.abspath(__file__)), "../build/convert")
+
+
 parser = argparse.ArgumentParser(description='Convert a TVM model into a Clockwork model')
 parser.add_argument("input_dir", metavar="INDIR", type=str, help="Base directory where TVM models exist.  The utility expects multiple models, one per batch size, each in a subdirectory.")
 parser.add_argument("output_dir", metavar="OUTDIR", type=str, help="Output directory.  Directory will be created if it does not exist.")
@@ -75,7 +78,7 @@ def convert(args):
 	print("The following command will run:")
 
 	pargs = [str(v) for v in [
-		"../build/convert",
+		convert_exec,
 		"-o", args.output_dir,
 		"-p", args.page_size
 	] + [x for m in models for x in m]]