Add GCE Windows compile bots as a 10% CQ experiment

These are Win2008R2 bots in GCE.  They're in production for Windows Swarm
Deterministic Build builder, and ran several successful builds on the try waterfall.

BUG=303794

Review URL: https://codereview.chromium.org/1151763014

Cr-Commit-Position: refs/heads/master@{#333191}

infra/config/cq.cfg

@@ -92,6 +92,10 @@ verifiers {
         name: "win8_chromium_ng"
         experiment_percentage: 0.1
       }
+      builders {
+        name: "win_chromium_compile_dbg_ng_exp"
+        experiment_percentage: 0.1
+      }
       builders { name: "win8_chromium_rel" }
       builders { name: "win_chromium_compile_dbg_ng" }
       builders { name: "win_chromium_rel_ng" }