Added specs for defined?(__FILE__) and friends.
Fixed defined? for __ENCODING__, __FILE__. Fixes #2605.
Add Kernel#autoload specs when Object is frozen
Update and improve some Kernel#taint specs

* Update for 2.1 Symbol changes(MRI-r42974 from ticket-8906)
* Fix indent
* Add specs for Bignum and Float
Add Kernel#frozen? specs for some immediates
Update failing Kernel#{taint,frozen?} spec tags
Merge pull request #2607 from kachick/spec-kernel-autoload-on_frozen_object

Add Kernel#autoload specs when Object is frozen
Merge pull request #2608 from kachick/spec-kernel-taint-frozen

Update some Kernel#{taint,frozen?} specs
Added specs for defined? with expressions.
Fixed defined? for more expressions. Fixes #2611.
Merge remote-tracking branch 'origin/master' into compiler

Conflicts:
	lib/compiler/ast/control_flow.rb
	lib/compiler/ast/encoding.rb
	lib/compiler/ast/file.rb