Added support for properly building and running isolates in recipes.

scripts/slave/recipes/gpu/build_and_test.expected/mac_release_skip_checkout.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]/gclient.py",
       "runhooks"
     ],
     "env": {
-      "GYP_DEFINES": "clang=1 component=static_library disable_glibcxx_debug=1 internal_gles2_conform_tests=1 target_arch=ia32",
+      "GYP_DEFINES": "clang=1 component=static_library disable_glibcxx_debug=1 internal_gles2_conform_tests=1 target_arch=ia32 test_isolation_mode=hashtable test_isolation_outdir=https://isolateserver.appspot.com",
       "GYP_GENERATORS": "ninja"
     },
     "name": "gclient runhooks"
   },
   {
     "abort_on_failure": true,
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/compile.py",
@@ skipping 79 matching lines @@
       "[BUILD]/scripts/slave/runtest.py",
       "--target",
       "Release",
       "--build-dir",
       "[SLAVE_BUILD]/src/out",
       "--no-xvfb",
       "--factory-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"branch\": \"master\", \"build_config\": \"Release\", \"buildername\": \"TestBuilder\", \"buildnumber\": 571, \"mastername\": \"chromium.testing.master\", \"project\": \"\", \"recipe\": \"gpu/build_and_test\", \"repository\": \"https://chromium.googlesource.com/chromium/src.git\", \"revision\": \"c14d891d44f0afff64e56ed7c9702df1d807b1ee\", \"skip_checkout\": true, \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
       "--build-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"branch\": \"master\", \"build_config\": \"Release\", \"buildername\": \"TestBuilder\", \"buildnumber\": 571, \"mastername\": \"chromium.testing.master\", \"project\": \"\", \"recipe\": \"gpu/build_and_test\", \"repository\": \"https://chromium.googlesource.com/chromium/src.git\", \"revision\": \"c14d891d44f0afff64e56ed7c9702df1d807b1ee\", \"skip_checkout\": true, \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
-      "gl_tests"
+      "angle_unittests"
     ],
-    "name": "gl_tests"
+    "name": "angle_unittests"
   },
   {
     "always_run": true,
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/runtest.py",
       "--target",
       "Release",
       "--build-dir",
       "[SLAVE_BUILD]/src/out",
       "--no-xvfb",
       "--factory-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"branch\": \"master\", \"build_config\": \"Release\", \"buildername\": \"TestBuilder\", \"buildnumber\": 571, \"mastername\": \"chromium.testing.master\", \"project\": \"\", \"recipe\": \"gpu/build_and_test\", \"repository\": \"https://chromium.googlesource.com/chromium/src.git\", \"revision\": \"c14d891d44f0afff64e56ed7c9702df1d807b1ee\", \"skip_checkout\": true, \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
       "--build-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"branch\": \"master\", \"build_config\": \"Release\", \"buildername\": \"TestBuilder\", \"buildnumber\": 571, \"mastername\": \"chromium.testing.master\", \"project\": \"\", \"recipe\": \"gpu/build_and_test\", \"repository\": \"https://chromium.googlesource.com/chromium/src.git\", \"revision\": \"c14d891d44f0afff64e56ed7c9702df1d807b1ee\", \"skip_checkout\": true, \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
-      "angle_unittests"
+      "--run-python-script",
+      "[SLAVE_BUILD]/src/tools/swarming_client/run_isolated.py",
+      "-H",
+      "6e784864abbeeff7499c15f75b904851d633c187",
+      "-I",
+      "https://isolateserver.appspot.com"
     ],
-    "name": "angle_unittests"
+    "name": "gl_tests"
   },
   {
     "allow_subannotations": true,
     "always_run": true,
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/runtest.py",
       "--target",
       "Release",
@@ skipping 248 matching lines @@
       "--test-type=tab_capture_performance_tests",
       "performance_browser_tests",
       "--enable-gpu",
       "--test-launcher-jobs=1",
       "--test-launcher-print-test-stdio=always",
       "--gtest_filter=TabCapturePerformanceTest*"
     ],
     "name": "tab_capture_performance_tests"
   }
 ]