Introduce mkgrokdump to update tools/v8heapconst.py.

test/BUILD.gn

 # Copyright 2016 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("../gni/isolate.gni")
 import("../gni/v8.gni")
 
 group("gn_all") {
   testonly = true
 
   deps = [
     ":default_tests",
     "inspector:inspector-test",
+    "mkgrokdump:mkgrokdump",
   ]
 
   if (host_os != "mac" || !is_android) {
     # These items don't compile for Android on Mac.
     deps += [
       "cctest:cctest",
       "cctest:generate-bytecode-expectations",
       "unittests:unittests",
     ]
   }
@@ skipping 17 matching lines @@
   testonly = true
 
   if (v8_test_isolation_mode != "noop") {
     deps = [
       ":cctest_run",
       ":fuzzer_run",
       ":inspector-test_run",
       ":intl_run",
       ":message_run",
       ":mjsunit_run",
+      ":mkgrokdump_run",
       ":preparser_run",
       ":unittests_run",
     ]
   }
 }
 
 v8_isolate_run("bot_default") {
   deps = [
     ":default_tests",
     ":webkit_run",
@@ skipping 127 matching lines @@
   isolate = "unittests/unittests.isolate"
 }
 
 v8_isolate_run("webkit") {
   deps = [
     "..:d8_run",
   ]
 
   isolate = "webkit/webkit.isolate"
 }
+
+v8_isolate_run("mkgrokdump") {

[Michael Achenbach, 2017/04/13 12:12:34]

nit: The others are somewhat alpha sorted. Maybe move up?

+  deps = [
+    "mkgrokdump:mkgrokdump",
+  ]
+
+  isolate = "mkgrokdump/mkgrokdump.isolate"
+}