Bump mmtk-core

Fixes a bug where there is an infinite loop when MMTK_HEAP_MIN is small.

Author: peterzhu2118

gc/mmtk/Cargo.lock

@@ -26,7 +26,7 @@ features = ["is_mmtk_object", "object_pinning", "sticky_immix_non_moving_nursery
 
 # Uncomment the following lines to use mmtk-core from the official repository.
 git = "https://github.com/mmtk/mmtk-core.git"
-rev = "c61e6c84f97ddb91e47d76914af2f7e462f1c7f8"
+rev = "051bc7470feef915c445305301e6113f86d3957b"
 
 # Uncomment the following line to use mmtk-core from a local repository.
 # path = "../../../mmtk-core"

gc/mmtk/Cargo.toml

@@ -34,10 +34,9 @@ def test_MMTK_HEAP_MIN
         assert_equal(1 * 1024 * 1024, GC.config[:mmtk_heap_min])
       RUBY
 
-      # TODO: uncomment this test when the infinite loop is fixed
-      # assert_separately([{ "MMTK_HEAP_MODE" => "dynamic", "MMTK_HEAP_MIN" => "1" }], <<~RUBY)
-      #   assert_equal(1, GC.config[:mmtk_heap_min])
-      # RUBY
+      assert_separately([{ "MMTK_HEAP_MODE" => "dynamic", "MMTK_HEAP_MIN" => "1" }], <<~RUBY)
+        assert_equal(1, GC.config[:mmtk_heap_min])
+      RUBY
 
       assert_separately([{ "MMTK_HEAP_MODE" => "dynamic", "MMTK_HEAP_MIN" => "10MiB", "MMTK_HEAP_MAX" => "1GiB" }], <<~RUBY)
         assert_equal(10 * 1024 * 1024, GC.config[:mmtk_heap_min])