Remove --tsp-compile functionality?

[tjprescott]

A frequent ask is to make the tool simpler, and currently, the ability to compile TypeSpec as a feature of the tool adds a lot of complexity. The tool actually only compares Swagger, so we could greatly simplify the tool by removing this feature.

Instead users would simply get their Swagger by running a regular tsp command:
tsp compile . --watch --emit=@azure-tools/autorest

Thus, as the TypeSpec is changed, the Swagger is recompiled and you can simply re-run the tool, pointing at the two Swagger locations.

This would also speed up the tool as the TypeSpec compilation seems to be slower when run through the tool than simply running tsp compile . --watch

[pshao25]

I agree this functionality is kind of redundant. But what is the cons if we keep it?

[tjprescott]

The main downside is complexity and maintenance of the tool. The TypeSpec compilation feature necessitates a bunch of additional flags and conditional logic that could have logic bugs. Additionally, compiling TypeSpec through the tool seems slower than simply compiling it manually (or using tsp compile --watch).