Make typechecking do the standard inits.
Make special env typecheck tests not run the code at module initialization.
Making test suite files all meet a standard interface.

All test suite files now export one identifier with the name 'tests'.
This allows for them to be treated the same across the test
infrastructure.
Make test files have mains that run the test case defined in them.
Make expanded syntax visible in test failures to aid debugging.
Make parse type and type annotation tests run at the right phase.
Fix raco test on relative paths.
racket/gui cocoa: fix "&" in labels

As of Mac OS X 10.8, `setTitleWithMnemonic:` doesn't strip away "&".
file/convertible: declare 'png@2x-bytes conversion variant

The 'png@2x-bytes variant is like 'png-bytes, but where the decoded
bytes are intended to be scaled by 1/2.

Consumers:

 - DrRacket's print handler

 - Scribble's HTML renderer

Producers:

 - `bitmap%`s where the scaling factor is 2

 - picts

Examples: Quick docs, docs for `images/icons/misc`, DrRacket interactions
for results of `images/icons/misc` functions.
GC bitmap @2x
path-element? should disallow '.' and '..'

Fix `path-element?` to check whether the name returned by split-path
is a path or a special entry. This behavior matches both the documentation
of `path-element?` and the implementation of `string->path-element`.
switch to unitless line-heights
racket/snip: fix `image-snip%` to convert to 'png@2x-bytes

An `image-snip%` converts to 'png@2x-bytes when its bitmap
has a backing scale of 2.
Minor cleanups to compiler.
Add caching for collects-relative->path.
Add TR helpers for new Racket error notation
Convert check-below.rkt error msgs to new format
fix bad interaction among JIT, 3-D macro, and bytecode reader

Closes PR 14186
fix (more) closure type tracking for a procedure with only an unused rest arg

Fixs the repair in fe12a32dc3

Relevant to PR 14259
Add a #lang for additional base type environments

These are for base type environments that get required
rather than loaded with #lang typed/racket.