Activate CSA implementation of Array.prototype.slice

Change-Id: I8f2dc21534562810e129f3830945bf68a181691f
Reviewed-on: https://chromium-review.googlesource.com/735379
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48862}

src/flag-definitions.h

@@ -739,7 +739,7 @@ DEFINE_BOOL(expose_trigger_failure, false, "expose trigger-failure extension")
 DEFINE_INT(stack_trace_limit, 10, "number of stack frames to capture")
 DEFINE_BOOL(builtins_in_stack_traces, false,
             "show built-in functions in stack traces")
-DEFINE_BOOL(enable_experimental_builtins, false,
+DEFINE_BOOL(enable_experimental_builtins, true,
             "enable new csa-based experimental builtins")
 
 // builtins.cc

test/mjsunit/mjsunit.status

@@ -48,9 +48,6 @@
   # This test non-deterministically runs out of memory on Windows ia32.
   'regress/regress-crbug-160010': [SKIP],
 
-  # This test should be skipped until the new CSA-based slice is activated.
-  'splice-proxy': [SKIP],
-
   # Issue 3784: setters-on-elements is flaky
   'setters-on-elements': [PASS, FAIL],