src/goTest: fix test run cancellation

Fixes golang/vscode-go#1726

Change-Id: I7cdd3e79601305b1ca8961ab323f4c6b6564ba61
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/345729
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Trust: Hyang-Ah Hana Kim <hyangah@gmail.com>
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
diff --git a/src/goTest/run.ts b/src/goTest/run.ts
index 1bd6382..536b799 100644
--- a/src/goTest/run.ts
+++ b/src/goTest/run.ts
@@ -227,6 +227,10 @@
 					this.markComplete(benchmarks, complete, (x) => run.skipped(x));
 				}
 			}
+
+			if (token?.isCancellationRequested) {
+				break;
+			}
 		}
 
 		run.end();