merge revision(s) 39809,39834,39837: [Backport #8132]

	* test/win32ole/test_err_in_callback.rb
	  (TestErrInCallBack#test_err_in_callback): shouldn't create a file in
	  source directory.

	* test/win32ole/test_err_in_callback.rb (TestErrInCallBack#setup): use
	  relative path to get rid of "too long commandline" error.
	  the top of build directory.

	* test/win32ole/test_err_in_callback.rb (TestErrInCallBack#setup):
	  allow using different root for source and build directories.
	  this may fixes a minor problem of r39834.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@39851 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 39835: [Backport #8058]

	* test/rubygems/test_gem_installer.rb (test_install_extension_flat):
	  use ruby in build directory in case ruby is not installed.
	  [ruby-core:53265] [Bug #8058]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@39852 b2dd03c8-39d4-4d8f-98ff-823fe69b080e