merge revision(s) r48222: [Backport #10464] [Backport #10465]

	* bignum.c (bary_mul_balance_with_mulfunc): Fix free work area
	  location.
	  [ruby-dev:48723] [Bug #10464]
	  [ruby-core:66044] [Bug #10465]
	  Reported by Kohji Nishihama.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@48272 b2dd03c8-39d4-4d8f-98ff-823fe69b080e