Fix Array#sample when pass count argument
Add Array#sample randomness specs
Remove Array#sample specs with high failury probability
Decrease failure probability for Array#sample randomness spec
Improve Kernel.#local_variables specs
Add a Kernel.#local_variables spec for eval
Fix Kernel.#local_variables for eval
Standardize a spelling on some specs

s/accessable/accessible/
Port File.realpath specs to File.realdirpath with adapted
Fix File.realdirpath

File.realdirpath is a similar method of File.realpath without exceptions.
It returns a fullpath of the argument. Not for dirname.
Implement Kernel#__dir__
Untag passing Kernel#__dir__ specs
Appropriately typedef call site function pointers
Fix IO#gets(limit) for encoding-related corner case
Merge pull request #2816 from kachick/kernel-local_variables

Kernel.#local_variables should not contain duplicated names
Merge pull request #2817 from kachick/realdirpath-and-__dir__

Fix File.realdirpath and Implement Kernel.#__dir__
Merge pull request #2819 from ryoqun/io-gets-limit-encoding

Fix IO#gets(limit) for encoding-related corner case
Merge remote-tracking branch 'ryoqun/call-site-typedef'
Added spec suggested by miraks in #2792.
Merge remote-tracking branch 'miraks/array_sample_fix'