tests/functional2: add framework for lang tests

This creates a framework similar to the old lang.sh from functional.
Some notable changes:
- instead of having a .flags file, a test.toml can declare flags
- additionally the test.toml can also declare extra files and multiple
runners for the given input file.
- there won't be any old tests hanging around anymore which weren't
deleted properly in the installation
- all files for a single test are defined decleratively and there won't
be any residues

Tests can be placed within the functional2/lang folder
most migrations should be rather clean

Implements: #825

Change-Id: I5f9149903ec5b078008969a4ae77305417c11475

misc/pre-commit.nix

@@ -52,11 +52,17 @@ pre-commit-run {
         "\\.drv$"
         "^tests/functional/lang/"
         ''\.patch$''
+        "^tests/functional2/.+\\.exp"
+        "^tests/functional2/.+\\.nix"
       ];
     };
     mixed-line-endings = {
       enable = true;
-      excludes = [ "^tests/functional/lang/" ];
+      excludes = [
+        "^tests/functional/lang/"
+        "^tests/functional2/.+\\.exp"
+        "^tests/functional2/.+\\.nix"
+      ];
     };
     release-notes = {
       enable = true;
@@ -110,6 +116,8 @@ pre-commit-run {
       stages = [ "pre-commit" ];
       excludes = [
         ''^tests/functional/lang/''
+        "^tests/functional2/.+\\.exp"
+        "^tests/functional2/.+\\.nix"
         ''\.patch$''
       ];
     };