Correctly remove the reference type when copying the thread function into the thread data area so we don't end up with a dangling reference

[SVN r46295]

libs/thread

@@ -1 +1 @@
-Subproject commit 9bebd7b35fc9fb60d4c64a8c447ee6212c51090a
+Subproject commit 851d6a987fcdd5b8d57859b284ae5adb19a3f497