Refactor libtest

[popzxc]

Short overview

libtest got refactored and splitted into smaller modules

Description

libtest module is already pretty big and hard to understand. Everything is mixed up: CLI, console output, test execution, etc.

This PR splits libtest into smaller logically-consistent modules, makes big functions smaller and more readable, and adds more comments, so libtest will be easier to understand and maintain.

Although there are a lot of changes, all the refactoring is "soft", meaning that no public interfaces were affected and nothing should be broken.

Thus this PR (at least should be) completely backward-compatible.

r? @wesleywiser
cc @Centril

[popzxc]

Well, seems like I've broken something =_= I will investigate it and fix tomorrow.

[popzxc]

Well, I forgot to re-export public bench interface. Everything is OK now (I hope).

[wesleywiser]

looks good and ci is green

[wesleywiser]

@bors r+

[bors]

📌 Commit a06b205 has been approved by wesleywiser

[bors]

⌛ Testing commit a06b205 with merge 2f58955296a705deee35afb6edd0edad6f489650...

[rust-highfive]

The job dist-various-1 of your PR failed (pretty log, raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

2019-10-20T19:42:13.8332950Z   local time: Sun Oct 20 19:42:13 UTC 2019
2019-10-20T19:42:13.8333154Z   network time: Sun, 20 Oct 2019 19:42:13 GMT
2019-10-20T19:42:13.8333335Z == end clock drift check ==
2019-10-20T19:42:15.1997551Z 
2019-10-20T19:42:15.2103341Z ##[error]Bash exited with code '1'.
2019-10-20T19:42:15.2141335Z ##[section]Starting: Upload CPU usage statistics
2019-10-20T19:42:15.2158367Z ==============================================================================
2019-10-20T19:42:15.2158464Z Task         : Bash
2019-10-20T19:42:15.2158713Z Description  : Run a Bash script on macOS, Linux, or Windows

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[bors]

💔 Test failed - checks-azure

[popzxc]

Hm. There was cfg(unix) attr for get_concurrency which was not required for cfg(target_os = "redox").

Should be fixed now.

P.S. It would be nice to have a tool which will check any configuration combination to be valid to detect things like this without waiting a merge queue to fail.

[wesleywiser]

@bors r+

[bors]

📌 Commit ae04dc8 has been approved by wesleywiser

[Centril]

@bors rollup=never p=1

[bors]

⌛ Testing commit ae04dc8 with merge 57bfb80...

[bors]

☀️ Test successful - checks-azure
Approved by: wesleywiser
Pushing 57bfb80 to master...

[RalfJung]

Looks like this broke the external compiletest-rs crate (used by Clippy and Miri): Manishearth/compiletest-rs#197

Miri is fine right now by using the "stable" feature flag. EDIT: looks like some types were made public again for clippy.