Remove in-tree test binary.

I presume this was accidentally committed.
rt::task: Make current_stack_segment public

Servo needs to tell SpiderMonkey about the stack bounds.
Forbid pub/priv where it has no effect

Closes #5495
debuginfo: Implemented proper handling of lexical scopes and variable shadowing.
debuginfo: Add support for argument shadowing.
debuginfo: Add some tests for visibiliy scopes within closures.
auto merge of #8423 : alexcrichton/rust/less-priv-again, r=bstrie

Closes #5495
Make rt::stack public

Fixes #8478.
Merge pull request #8432 from chris-morgan/remove-assert-eq-macro-fail-binary

Remove in-tree test binary.
auto merge of #8475 : kmcallister/rust/stack_segment, r=brson,brson

Servo needs to tell SpiderMonkey about the stack bounds.

r? @brson
auto merge of #8329 : michaelwoerister/rust/lexical_scopes_alt, r=graydon

This pull request re-implements handling of visibility scopes and source code positions in debug info. It should now be very stable and properly handle

+ variable shadowing
+ expanded code (macros and the new for-loop de-sugaring, for example)
+ variables in the middle of nested scopes
+ bindings declared in the head of match statement arms. 

all of which did not work at all or did not work reliably before. Those interested in a more detailed description of the problems at hand, I kindly refer to http://michaelwoerister.github.io/2013/08/03/visibility-scopes.html

Why doesn't the `populate_scope_map()` function use `syntax::visit`?
Because it would not improve this particular AST walker (see: https://github.com/michaelwoerister/rust/commit/69dc7908490b8b492e9730cb1c34fa83c2ef30eb#commitcomment-3781426)

Cheers,
Michael