Change suspend entrypoint to save all registers.

We avoid the need to save/restore registers in slow paths
and get significant code size savings. On Nexus 9, AOSP:
  - 32-bit boot.oat: -1.4MiB (-1.9%)
  - 64-bit boot.oat: -2.0MiB (-2.3%)
  - other 32-bit oat files in dalvik-cache: -200KiB (-1.7%)
  - other 64-bit oat files in dalvik-cache: -2.3MiB (-2.1%)

Test: Run ART test suite on host and Nexus 9 with gc stress.
Bug: 30212852
Change-Id: I7015afc1e7d30341618c9200a3dc9ae277afd134
diff --git a/oatdump/oatdump.cc b/oatdump/oatdump.cc
index 64349b5..532bccf 100644
--- a/oatdump/oatdump.cc
+++ b/oatdump/oatdump.cc
@@ -76,6 +76,7 @@
   "kCalleeSaveMethod",
   "kRefsOnlySaveMethod",
   "kRefsAndArgsSaveMethod",
+  "kSaveEverythingMethod",
 };
 
 const char* image_roots_descriptions_[] = {