[flags] Set owners for WebAssembly flags

NOTRY=true
NOPRESUBMIT=true
NOTREECHECKS=true

Change-Id: I691fff46ceb59f935f12b352a1f34b081728e302
Reviewed-on: https://chromium-review.googlesource.com/c/1345971Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610353}

chrome/browser/flag-metadata.json

@@ -1985,17 +1985,17 @@
   },
   {
     "name": "enable-webassembly",
-    // "owners": [ "your-team" ],
-    "expiry_milestone": 76
+    "owners": [ "titzer", "wasm-team@google.com" ],
+    "expiry_milestone": 72
   },
   {
     "name": "enable-webassembly-baseline",
-    // "owners": [ "your-team" ],
+    "owners": [ "clemensh", "wasm-team@google.com" ],
     "expiry_milestone": 76
   },
   {
     "name": "enable-webassembly-threads",
-    // "owners": [ "your-team" ],
+    "owners": [ "binji", "hablich", "wasm-team@google.com" ],
     "expiry_milestone": 76
   },
   {