Do not abort a child run when start another run

lib/spork/run_strategy/forking.rb

@@ -4,34 +4,24 @@ def self.available?
   end
 
   def run(argv, stderr, stdout)
-    abort if running?
-
     Spork.increase_process_counter
 
-    @child = ::Spork::Forker.new do
+    child = ::Spork::Forker.new do
       $stdout, $stderr = stdout, stderr
       load test_framework.helper_file
       Spork.exec_each_run
       result = test_framework.run_tests(argv, stderr, stdout)
       Spork.exec_after_each_run
       result
     end
-    @child.result
-  end
-
-  def abort
-    @child && @child.abort
+    child.result
   end
 
   def preload
     test_framework.preload
   end
 
-  def running?
-    @child && @child.running?
-  end
-
   def assert_ready!
     raise RuntimeError, "This process hasn't loaded the environment yet by loading the prefork block" unless Spork.using_spork?
   end
-end
+end