Roll jsshell/jsc to newer versions

(The automated infra to create new D8 versions has some issues atm)

Change-Id: I5a43566f763eb3d9efeba0f0cab0357a802b33b3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/351061
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: William Hesse <whesse@google.com>

DEPS

diff --git a/DEPS b/DEPS
index 044a285..03874f7 100644
--- a/DEPS
+++ b/DEPS
@@ -72,8 +72,8 @@
   # instructions. d8, the V8 shell, is always checked out.
   "checkout_javascript_engines": False,
   "d8_tag": "version:12.1.131",
-  "jsshell_tag": "version:120.0",
-  "jsc_tag": "version:273394",
+  "jsshell_tag": "version:122.0",
+  "jsc_tag": "version:274355",
 
   # https://chrome-infra-packages.appspot.com/p/fuchsia/third_party/clang
   "clang_version": "git_revision:c58bc24fcf678c55b0bf522be89eff070507a005",