Fixes multiple issues with stack traces leading to missing
stack trace lines. Also, we no longer put builtin context
on the line which *calls* the builtin as if it was a part
of the builtin itself.
Code for stack trace handling was centralized. We no longer
need traceElement argument in ~every function. Now the stack
trace state is kept solely in the interpreter.
Sort is something that is highly optimized in most languages
and users can expect it to be fast. We can piggyback on
the Go implementation.
This change results in 100x speedup on bench.06.jsonnet.
