Update isolate.gypi to support Swarming + move .isolate files

This updates the isolate.gypi copies we have to maintain in our
code repo to Chromium's revision 310ea93.
The changes about generating .isolated.gen.json files are needed
to support running with Swarming (https://www.chromium.org/developers/testing/isolated-testing)

Since isolated testing is now using a new launch script
in tools: isolate_driver.py, that's added to our links
script.

In order to use isolate_driver.py, the .isolate files must be in the
same directory as the test_name_run target is defined, which meant
I had to move around some of the isolate files and targets below
webrtc/modules.

BUG=497757
R=maruel@chromium.org
TBR=henrik.lundin@webrtc.org, mflodman@webrtc.org, niklas.enbom@webrtc.org
TESTED=Clobbered trybots:
git cl try -c --bot=linux_compile_rel --bot=mac_compile_rel --bot=win_compile_rel --bot=android_compile_rel --bot=ios_rel -m tryserver.webrtc

Review URL: https://codereview.webrtc.org/1373513002 .

Cr-Commit-Position: refs/heads/master@{#10081}
diff --git a/setup_links.py b/setup_links.py
index 1a155a7..44f3f07 100755
--- a/setup_links.py
+++ b/setup_links.py
@@ -105,6 +105,7 @@
 
 FILES = {
   'tools/find_depot_tools.py': None,
+  'tools/isolate_driver.py': None,
   'third_party/BUILD.gn': None,
 }