leverage caching for rendering traces

[vito]

previously it was possible to load a cached file and run it without a runtime but then fail to render its content in the trace printed to stderr:

error! call trace (oldest first):

   ┆ <fs>/project.bass:35:2..35:45
35 │   (github:check-hook event client git checks))
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

   ┆ <thunk: (.git) name:yPieviqhlsa6uTBhT-gpoQDbzpMyl1owqphA_l6wt0Y=>/bass/github.bass:3:4..54:66
   ! could not open frame source: no runtime configured for os=linux, arch=any

   ┆ (6 internal calls elided)
   ┆ <thunk: (.git) name:yPieviqhlsa6uTBhT-gpoQDbzpMyl1owqphA_l6wt0Y=>/bass/github.bass:5:6..17:68
   ! could not open frame source: no runtime configured for os=linux, arch=any

   ┆ (6 internal calls elided)
   ┆ <thunk: (.git) name:yPieviqhlsa6uTBhT-gpoQDbzpMyl1owqphA_l6wt0Y=>/bass/github.bass:9:8..9:71
   ! could not open frame source: no runtime configured for os=linux, arch=any

   ┆ <thunk: (.git) name:yPieviqhlsa6uTBhT-gpoQDbzpMyl1owqphA_l6wt0Y=>/bass/github.bass:57:4..59:27
   ! could not open frame source: no runtime configured for os=linux, arch=any

no runtime configured for os=linux, arch=any

live example here

now if it's able to get that far it'll use the cached file for rendering the actual code too.