Add specs for String#{[],slice} with untrusted Regexp
Add specs for Symbol#{[],slice} with untrusted Regexp
Fix {String,Symbol}#{[],slice} with untrusted Regexp

Symbol#{[],slice} with [Regexp, capture_index] is
depending String#subpattern too.
Merge pull request #2476 from kachick/string,symbol-slicer-infection

{String,Symbol}#{[],slice} with untrusted Regexp should copy the untrusted status to the returning value
Merge pull request #2474 from kachick/fix-enum-depend_size_on_1.8

Enumerable#count without arguments should prefer self.size on 1.8
Add specs for the external and internal encodings of IO.popen
Don't set IO.popen's internal encoding if it's the same as the external

Fixes #2427
Add tags for failing specs
Remove calls to removed function rb_str_flush
Remove unused ValueGenerator from Array
Merge pull request #2469 from kachick/spec-regexp-named_capture_sets_local-var

Add specs for `/regexp/ =~ "string"` with named captures should set local variables
Always check for local reference first when sending

The handling of a Regexp =~ local means we should check here if there is
a local before emitting a send. This is the easiest solution, otherwise
the parser would have been told about this knowledge.
Setup locals from Regexp =~

Fixes #2051 and #2466
Remove tags for now passing specs
Write specs for StopIteration#result

[1.9.1](https://github.com/ruby/ruby/blob/1306ae8a461b30fbc59aedea7262958cc5775137/enumerator.c#L792)
[1.9.2](https://github.com/ruby/ruby/blob/e80d0a9631cdfebc53c1a111eb2162fe3f1dc67c/enumerator.c#L1097-L1098)
Implement StopIteration#result
Fix Regexp#=~ matching for eval locals
Merge pull request #2477 from kachick/implement-stopiteration-result

Implement StopIteration#result
Merge pull request #2467 from kachick/fix-module-remove,undef_method

Fix Module#{undef_method,remove_method}
Explicitly sort the added local variables

Fixes random CI failures because it would not be defined ordering wise.
This makes sure we always set up the locals in order they were defined
on the regular expression.