tests(f2/repl): migrate stacktrace tests

Change-Id: Ic6795f22d68aea113fa2037cbd0a731ac5e698f8

tests/functional2/repl_characterization/stacktrace/relative.md

@@ -0,0 +1,105 @@
+---
+args: ['--debugger']
+---
+
+```nix
+let f = _: throw "x_x"; x = f 5; in x
+```
+```output
+error: x_x
+
+Added 3 variables.
+```
+
+
+absolute indices still work:
+```nix
+:st 1
+```
+```output
+
+1: while calling a function
+«string»:1:12
+
+     1| let f = _: throw "x_x"; x = f 5; in x
+      |            ^
+
+Env level 0
+static: _ 
+
+Env level 1
+static: f x 
+
+Env level 2
+static: 
+
+Env level 3
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 3 variables.
+
+```
+
+
+index with + goes up the stack relative to current (1 in this case):
+```nix
+:st +3
+```
+```output
+
+4: while evaluating a 'let' expression
+«string»:1:1
+
+     1| let f = _: throw "x_x"; x = f 5; in x
+      | ^
+
+Env level 0
+static: f x 
+
+Env level 1
+static: 
+
+Env level 2
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 2 variables.
+
+```
+
+
+
+index with - goes down and is also relative to current(4):
+
+```nix
+:st -1
+```
+```output
+
+3: while calling a function
+«string»:1:29
+
+     1| let f = _: throw "x_x"; x = f 5; in x
+      |                             ^
+
+Env level 0
+static: f x 
+
+Env level 1
+static: 
+
+Env level 2
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 2 variables.
+
+```
+
+
+quit
+```nix
+:quit
+```
+```output
+error: x_x
+
+```