LUCI: Have trybot android-marshmallow-x86-rel running on the same pool as arm64

The bot pool looks sufficient for the extra traffic: http://shortn/_uTq3bMFtkS

Bug: 997376
Change-Id: I19b127b71802c652137c94f54632395bf965f31c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2387123Reviewed-by: Yoshisato Yanagisawa <yyanagisawa@google.com>
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Commit-Queue: Haiyang Pan <hypan@google.com>
Cr-Commit-Position: refs/heads/master@{#804294}

infra/config/generated/cr-buildbucket.cfg

@@ -17403,17 +17403,17 @@ buckets {
       swarming_host: "chromium-swarm.appspot.com"
       swarming_tags: "vpython:native-python-wrapper"
       dimensions: "builderless:1"
-      dimensions: "cores:8"
+      dimensions: "cores:16"
       dimensions: "cpu:x86-64"
       dimensions: "os:Ubuntu-16.04"
       dimensions: "pool:luci.chromium.try"
-      dimensions: "ssd:0"
+      dimensions: "ssd:1"
       exe {
         cipd_package: "infra/recipe_bundles/chromium.googlesource.com/chromium/tools/build"
         cipd_version: "refs/heads/master"
         cmd: "recipes"
       }
-      properties: "{\"$build/goma\":{\"enable_ats\":true,\"jobs\":150,\"rpc_extra_params\":\"?prod\",\"server_host\":\"goma.chromium.org\"},\"$kitchen\":{\"devshell\":true,\"git_auth\":true},\"builder_group\":\"tryserver.chromium.android\",\"recipe\":\"chromium_trybot\"}"
+      properties: "{\"$build/goma\":{\"enable_ats\":true,\"jobs\":300,\"rpc_extra_params\":\"?prod\",\"server_host\":\"goma.chromium.org\"},\"$kitchen\":{\"devshell\":true,\"git_auth\":true},\"builder_group\":\"tryserver.chromium.android\",\"recipe\":\"chromium_trybot\"}"
       execution_timeout_secs: 14400
       expiration_secs: 7200
       caches {

infra/config/subprojects/chromium/try.star

@@ -252,7 +252,9 @@ try_.chromium_android_builder(
 try_.chromium_android_builder(
     name = "android-marshmallow-x86-rel",
     branch_selector = branches.STANDARD_RELEASES,
-    goma_jobs = goma.jobs.J150,
+    cores = 16,
+    goma_jobs = goma.jobs.J300,
+    ssd = True,
     tryjob = try_.job(
         experiment_percentage = 5,
     ),