Use Primitive.gc_force instead of GC.start in spec/truffle

Author: eregon

spec/truffle/gc/time_spec.rb

@@ -1,3 +1,5 @@
+# truffleruby_primitives: true
+
 # Copyright (c) 2015, 2019 Oracle and/or its affiliates. All rights reserved. This
 # code is released under a tri EPL/GPL/LGPL license. You can use it,
 # redistribute it and/or modify it under the terms of the:
@@ -16,11 +18,7 @@
 
   it "increases as collections are run" do
     time_before = GC.time
-    i = 0
-    while GC.time <= time_before and i < 10
-      GC.start
-      i += 1
-    end
+    Primitive.gc_force
     GC.time.should > time_before
   end
 

spec/truffle/objspace/undefine_finalizer_spec.rb

@@ -1,3 +1,5 @@
+# truffleruby_primitives: true
+
 # Copyright (c) 2017, 2019 Oracle and/or its affiliates. All rights reserved. This
 # code is released under a tri EPL/GPL/LGPL license. You can use it,
 # redistribute it and/or modify it under the terms of the:
@@ -25,7 +27,7 @@
       ObjectSpace.undefine_finalizer object
       ObjectSpace.reachable_objects_from(object).should_not include(finalizer)
     end
-    GC.start
+    Primitive.gc_force
     Truffle::Debug.drain_finalization_queue               # Not needed for correctness
     channel.try_receive.should be_nil
   end