[infra] Mac VMs running NativeFonts tasks were updated

Change-Id: I6706f32162206a6cfaeaf71f9a42a5ba66379148
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/335042
Commit-Queue: Eric Boren <borenet@google.com>
Reviewed-by: Ravi Mistry <rmistry@google.com>

infra/bots/gen_tasks_logic/gen_tasks_logic.go

@@ -565,6 +565,10 @@ func (b *taskBuilder) defaultSwarmDimensions() {
 			// ChOps VMs are at a newer version of MacOS.
 			d["os"] = "Mac-10.14.6"
 		}
+		if os == "Mac10.15" && b.parts["model"] == "VMware7.1" {
+			// ChOps VMs are at a newer version of MacOS.
+			d["os"] = "Mac-10.15.7"
+		}
 		if b.parts["model"] == "LenovoYogaC630" {
 			// This is currently a unique snowflake.
 			d["os"] = "Windows-10"

infra/bots/tasks.json

@@ -43960,7 +43960,7 @@
       ],
       "dimensions": [
         "cpu:x86-64-E5-2697_v2",
-        "os:Mac-10.15.1",
+        "os:Mac-10.15.7",
         "pool:Skia"
       ],
       "env_prefixes": {