Add flag to "am start" to enable native debugging

Specifying the new flag will enable several features in the runtime
required by the native debugger to debug Java and C++ code at the same
time.

The enabled features:
* Force JIT (never use the interpreter)
* Debug info generation
* Disbale some optimizations

Change-Id: Iaf5ab649715a0c274bd1b0fc64e483705da53cd0
diff --git a/core/java/com/android/internal/os/Zygote.java b/core/java/com/android/internal/os/Zygote.java
index d23f26d..919254a 100644
--- a/core/java/com/android/internal/os/Zygote.java
+++ b/core/java/com/android/internal/os/Zygote.java
@@ -41,6 +41,10 @@
     public static final int DEBUG_ENABLE_JNI_LOGGING = 1 << 4;
     /** Force generation of native debugging information. */
     public static final int DEBUG_GENERATE_DEBUG_INFO = 1 << 5;
+    /** Always use JIT-ed code. */
+    public static final int DEBUG_ALWAYS_JIT = 1 << 6;
+    /** Make the code debuggable with turning off some optimizations. */
+    public static final int DEBUG_NATIVE_DEBUGGABLE = 1 << 7;
 
     /** No external storage should be mounted. */
     public static final int MOUNT_EXTERNAL_NONE = 0;