win32.c: wait until exit

* win32/win32.c (waitpid): should not return 0 but wait until exit
  unless WNOHANG is given.  waiting huge process may return while
  active, for some reason.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41447 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
test_process.rb: redirect to null

* test/ruby/test_process.rb (test_no_curdir): since standard handles
  cannot close on Windows, redirect to null device.

* test/ruby/test_process.rb (assert_fail_too_long_path): ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41448 b2dd03c8-39d4-4d8f-98ff-823fe69b080e