Makes the primary Jit table growable.  Also includes a change suggested earlier by Dan to use a pre-defined mask in the hash function.  Reduce the default JitTable size from 2048 entries to 512 entries.
Update per Ben's comments.
diff --git a/vm/Init.c b/vm/Init.c
index 5295f49..7486ad9 100644
--- a/vm/Init.c
+++ b/vm/Init.c
@@ -1011,7 +1011,8 @@
      *        frameworks/base/core/jni/AndroidRuntime.cpp
      */
     gDvmJit.blockingMode = false;
-    gDvmJit.maxTableEntries = 2048;
+    gDvmJit.jitTableSize = 512;
+    gDvmJit.jitTableMask = gDvmJit.jitTableSize - 1;
     gDvmJit.threshold = 200;
 #else
     gDvm.executionMode = kExecutionModeInterpFast;