Add features for genimmix and stickyimmix (#228)

We currently allow build with a fixed plan to work with the current performance CI. mmtk/mmtk-core#901 attempts to add more plans to our performance CI. This PR adds some missing features for genimmix and stickyimmix. 

We do not need those plans once we move to the new `running-ng` scripts.

Author: qinsoon

mmtk/Cargo.toml

@@ -62,3 +62,5 @@ gencopy = []
 marksweep = []
 pageprotect = []
 immix = []
+genimmix = []
+stickyimmix = []

mmtk/src/api.rs

@@ -72,6 +72,10 @@ pub extern "C" fn openjdk_gc_init(calls: *const OpenJDK_Upcalls) {
             Some(PlanSelector::PageProtect)
         } else if cfg!(feature = "immix") {
             Some(PlanSelector::Immix)
+        } else if cfg!(feature = "genimmix") {
+            Some(PlanSelector::GenImmix)
+        } else if cfg!(feature = "stickyimmix") {
+            Some(PlanSelector::StickyImmix)
         } else {
             None
         };