[CI] Bump max nodes in windows 2022 pools to 16

This puts them in line with the existing windows node pool so that we can
smoothly transition once we land the patch in the monorepo to move everything
over.

Author: boomanaiden154

premerge/gke_cluster/main.tf

@@ -147,11 +147,9 @@ resource "google_container_node_pool" "llvm_premerge_windows_2022" {
   cluster            = google_container_cluster.llvm_premerge.name
   initial_node_count = 0
 
-  # TODO(boomanaiden154): Bump this to full capacity (16 nodes) once we are
-  # ready to switch over to server 2022.
   autoscaling {
     total_min_node_count = 0
-    total_max_node_count = 2
+    total_max_node_count = 16
   }
 
   # We do not set a taint for the windows nodes as kubernetes by default sets