Add spec for Range#each when Symbol elemenets on X19
Fix Range#each for multi-character Symbol elements. Fixes #2149
Simplify Range#each for String elements
Adjust Range#each for X18

Ruby 1.8.7 can not generate Range objects from Symbol elements

:a..:b #=> ArgumentError: bad value for range

This commit removes verbose dealing for Symbol on X18
More Kernel.chop[!] specs.
Encoding related specs for Kernel.chop, .chomp.
Specs for #previous_byte_index.
Cleaned up String#chop[!] specs.
String#chomp, #chop specs for multibyte \n, \r.
Rewrote String#chomp[!] specs.
Fixed String#cho[m]p[!]. Closes #2079.
Merge pull request #2150 from kachick/fix_improve-range_each

Fix Range#each for Symbol elements and some simplifications
Remove stale comment
Add a spec for Proc#== with rb_proc_new
Also consider @bound_method for equality
Add various specs for Proc#{inspect,source_location}
Remove extra spaces around @ for consistency
Correctly override #source_location at Proc::Method

Also, to make it happen, this versionizes Proc::Method#inspect.
Fix Proc#source_location because @block can be nil