Update mmtk and ruby repo rev

Author: wks

mmtk/Cargo.lock

@@ -12,7 +12,7 @@ edition = "2021"
 # Metadata for the Ruby repository
 [package.metadata.ci-repos.ruby]
 repo = "mmtk/ruby" # This is used by actions/checkout, so the format is "owner/repo", not URL.
-rev = "b96430a7db726ddeb9907ee5dbe36466c6e23344"
+rev = "2b04d0c6d06c2d94fa6e9ced0e4395f790137464"
 
 [lib]
 name = "mmtk_ruby"
@@ -36,11 +36,11 @@ probe = "0.5"
 features = ["is_mmtk_object", "object_pinning"]
 
 # Uncomment the following lines to use mmtk-core from the official repository.
-#git = "https://github.com/wks/mmtk-core.git"
-#rev = "7cb0b2c12be341c084e03f2cd943fad8ac088f83"
+git = "https://github.com/wks/mmtk-core.git"
+rev = "b968d7350a11c048c72a965912943a0f5235dd35"
 
 # Uncomment the following line to use mmtk-core from a local repository.
-path = "../../mmtk-core"
+#path = "../../mmtk-core"
 
 [features]
 default = []