[ios] default clang mac (ToTMac*) builders to OS Mac-10.15

The machines have successfully upgraded to Mac 10.15, so we're
setting the OS dimension accordingly.

Bug: 1135264
Change-Id: Ie1bcf9e434e75510a673f93ac430474c5fbcf7a6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2450896
Auto-Submit: Jeff Yoon <jeffyoon@chromium.org>
Commit-Queue: Garrett Beaty <gbeaty@chromium.org>
Reviewed-by: Garrett Beaty <gbeaty@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814278}

infra/config/generated/cr-buildbucket.cfg

@@ -7206,7 +7206,7 @@ buckets {
       dimensions: "builderless:1"
       dimensions: "cores:24"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Mac-10.14|Mac-10.15"
+      dimensions: "os:Mac-10.15"
       dimensions: "pool:luci.chromium.ci"
       dimensions: "ssd:1"
       exe {
@@ -7235,7 +7235,7 @@ buckets {
       dimensions: "builderless:1"
       dimensions: "cores:24"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Mac-10.14|Mac-10.15"
+      dimensions: "os:Mac-10.15"
       dimensions: "pool:luci.chromium.ci"
       dimensions: "ssd:1"
       exe {
@@ -7264,7 +7264,7 @@ buckets {
       dimensions: "builderless:1"
       dimensions: "cores:24"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Mac-10.14|Mac-10.15"
+      dimensions: "os:Mac-10.15"
       dimensions: "pool:luci.chromium.ci"
       dimensions: "ssd:1"
       exe {
@@ -7293,7 +7293,7 @@ buckets {
       dimensions: "builderless:1"
       dimensions: "cores:24"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Mac-10.14|Mac-10.15"
+      dimensions: "os:Mac-10.15"
       dimensions: "pool:luci.chromium.ci"
       dimensions: "ssd:1"
       exe {

infra/config/lib/builders.star

@@ -67,9 +67,6 @@ os = struct(
     MAC_11_0 = os_enum("Mac-11.0", os_category.MAC),
     # TODO(crbug/1121185): Remove 10.13 once builders have been migrated to 10.15.
     MAC_DEFAULT = os_enum("Mac-10.13|Mac-10.15", os_category.MAC),
-    # TODO(crbug/1135264): ToTMac* bots need this to ensure they don't break
-    # during the upgrade to 10.15.
-    MAC_10_14_AND_15 = os_enum("Mac-10.14|Mac-10.15", os_category.MAC),
     MAC_ANY = os_enum("Mac", os_category.MAC),
     WINDOWS_7 = os_enum("Windows-7", os_category.WINDOWS),
     WINDOWS_8_1 = os_enum("Windows-8.1", os_category.WINDOWS),

infra/config/lib/ci.star

@@ -600,7 +600,7 @@ def clang_mac_builder(*, name, cores = 24, **kwargs):
     return clang_builder(
         name = name,
         cores = cores,
-        os = builders.os.MAC_10_14_AND_15,
+        os = builders.os.MAC_10_15,
         ssd = True,
         properties = {
             "xcode_build_version": "11a1027",