ARM64: Remove suspend register.

It also clean up build/remove frame used by JNI compiler and generates
stp/ldp instead of str/ldr. Also x19 has been unblocked in both quick and
optimizing compiler.

Change-Id: Idbeac0942265f493266b2ef9b7a65bb4054f0e2d
diff --git a/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc b/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
index 8351e22..2e813c8 100644
--- a/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
+++ b/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
@@ -88,7 +88,7 @@
   // | LR         |
   // | X29        |
   // |  :         |
-  // | X20        |
+  // | X19        |
   // | X7         |
   // | :          |
   // | X1         |