feat(tvix/glue): Implement builtins.storePath r/8217

This one's relatively simple - we just check if the store path exists,
and if it does we make a new contextful string containing the store path
as its only context element.

Automatic testing seems tricky for this (I think?) so I tested it
manually:

tvix-repl> builtins.storePath /nix/store/yn46i4xx5alh7gs6fpkxk430i34rp2q9-hello-2.12.1
=> "/nix/store/yn46i4xx5alh7gs6fpkxk430i34rp2q9-hello-2.12.1" :: string

Change-Id: I8a0d9726e4102ab872c53c2419679c2c855a5a18
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11696
Tested-by: BuildkiteCI
Autosubmit: aspen <root@gws.fyi>
Reviewed-by: flokli <flokli@flokli.de>

0 files changed, 0 insertions, 0 deletions