Reland of [heap] Fix CompactionSpace test and move to unittests

test/unittests/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/v8.gni")
 
 v8_executable("unittests") {
   testonly = true
 
   sources = [
@@ skipping 91 matching lines @@
     "eh-frame-writer-unittest.cc",
     "heap/bitmap-unittest.cc",
     "heap/embedder-tracing-unittest.cc",
     "heap/gc-idle-time-handler-unittest.cc",
     "heap/gc-tracer-unittest.cc",
     "heap/heap-unittest.cc",
     "heap/marking-unittest.cc",
     "heap/memory-reducer-unittest.cc",
     "heap/scavenge-job-unittest.cc",
     "heap/slot-set-unittest.cc",
+    "heap/spaces-unittest.cc",
     "heap/unmapper-unittest.cc",
     "interpreter/bytecode-array-builder-unittest.cc",
     "interpreter/bytecode-array-iterator-unittest.cc",
     "interpreter/bytecode-array-random-iterator-unittest.cc",
     "interpreter/bytecode-array-writer-unittest.cc",
     "interpreter/bytecode-dead-code-optimizer-unittest.cc",
     "interpreter/bytecode-decoder-unittest.cc",
     "interpreter/bytecode-operands-unittest.cc",
     "interpreter/bytecode-peephole-optimizer-unittest.cc",
     "interpreter/bytecode-pipeline-unittest.cc",
@@ skipping 75 matching lines @@
     deps += [ "//third_party/icu" ]
   }
 
   if (is_win) {
     # This warning is benignly triggered by the U16 and U32 macros in
     # bytecode-utils.h.
     # C4309: 'static_cast': truncation of constant value
     cflags = [ "/wd4309" ]
   }
 }