Rename callee save enumerators.

And related image method enumerators, macros, etc.
Clean up some entrypoint assembly comments.

This is a follow-up to
    https://android-review.googlesource.com/252348

Test: Run ART test suite on host and Nexus 9.
Bug: 30212852
Change-Id: I2707342d4255c88c547655be83ed97a67e12ae9e
diff --git a/runtime/entrypoints/quick/quick_instrumentation_entrypoints.cc b/runtime/entrypoints/quick/quick_instrumentation_entrypoints.cc
index b5e560f..82d5467 100644
--- a/runtime/entrypoints/quick/quick_instrumentation_entrypoints.cc
+++ b/runtime/entrypoints/quick/quick_instrumentation_entrypoints.cc
@@ -56,7 +56,7 @@
   CHECK(!self->IsExceptionPending()) << "Enter instrumentation exit stub with pending exception "
                                      << self->GetException()->Dump();
   // Compute address of return PC and sanity check that it currently holds 0.
-  size_t return_pc_offset = GetCalleeSaveReturnPcOffset(kRuntimeISA, Runtime::kRefsOnly);
+  size_t return_pc_offset = GetCalleeSaveReturnPcOffset(kRuntimeISA, Runtime::kSaveRefsOnly);
   uintptr_t* return_pc = reinterpret_cast<uintptr_t*>(reinterpret_cast<uint8_t*>(sp) +
                                                       return_pc_offset);
   CHECK_EQ(*return_pc, 0U);