Add gctype device config property for GC experiments

Added to the runtime_native namespace.

The new property overrides dalvik.vm.gctype if it's set.

Bug: 120794191
Test: adb shell device_config put runtime_native gctype CC,preverify
Test: adb reboot

Change-Id: I30a2a3bcfb83f502f168c0d8588d80982a5f7d76
diff --git a/core/jni/Android.bp b/core/jni/Android.bp
index 9afd5d0..51a3b48 100644
--- a/core/jni/Android.bp
+++ b/core/jni/Android.bp
@@ -301,6 +301,7 @@
         "libhwui",
         "libdl",
         "libstatslog",
+        "server_configurable_flags",
     ],
 
     generated_sources: ["android_util_StatsLog.cpp"],