string.c: shrink too big buffer

* string.c (rb_str_resize): shrink the buffer even if new length
  is same but it is enough smaller than the capacity.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46408 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-06-12

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46409 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
file.c: shrink expanded path

* file.c (expand_path): shrink expanded path which no longer needs
  rooms to append.  [ruby-core:63114] [Bug #9934]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46410 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
string.c: shrink before freezing

* string.c (rb_str_freeze): shrink the buffer before freezing, as
  pointed out by Eric Wong at [ruby-core:63119].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46411 b2dd03c8-39d4-4d8f-98ff-823fe69b080e