Revert "Revert "Upgrade to 5.0.71.48"" DO NOT MERGE

This reverts commit f2e3994fa5148cc3d9946666f0b0596290192b0e,
and updates the x64 makefile properly so it doesn't break that
build.

FPIIM-449

Change-Id: Ib83e35bfbae6af627451c926a9650ec57c045605
(cherry picked from commit 109988c7ccb6f3fd1a58574fa3dfb88beaef6632)
diff --git a/src/elements-kind.cc b/src/elements-kind.cc
index 0d29c30..7bb75c4 100644
--- a/src/elements-kind.cc
+++ b/src/elements-kind.cc
@@ -37,7 +37,12 @@
     case DICTIONARY_ELEMENTS:
     case FAST_SLOPPY_ARGUMENTS_ELEMENTS:
     case SLOW_SLOPPY_ARGUMENTS_ELEMENTS:
+    case FAST_STRING_WRAPPER_ELEMENTS:
+    case SLOW_STRING_WRAPPER_ELEMENTS:
       return kPointerSizeLog2;
+    case NO_ELEMENTS:
+      UNREACHABLE();
+      return 0;
   }
   UNREACHABLE();
   return 0;