* gc.c (vm_malloc_increase): check GVL before gc_rest_sweep().
  vm_malloc_increase() can be called without GVL.
  However, gc_rest_sweep() assumes acquiring GVL.
  To avoid this problem, check GVL before gc_rest_sweep().
  [Bug #9090]
  This workaround introduces possibility to set malloc_limit as
  wrong value (*1). However, this may be rare case. So I commit it.
  *1: Without rest_sweep() here, gc_rest_sweep() can decrease
      malloc_increase due to ruby_sized_xfree().



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43574 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
commit miss from r43573


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43575 b2dd03c8-39d4-4d8f-98ff-823fe69b080e