roachtest: mvcc_gc increase GC waiting timeouts

Test waits for mvcc gc queue to collect old data. Replicas are
enqueued for GC asynchronously and it could take long time for
garbage to get collected which causes test to fail.
This commit bumps retry timeout to remove false negatives.

Release note: None

Fixes: #90020

pkg/cmd/roachtest/tests/mvcc_gc.go

@@ -70,6 +70,8 @@ func runMVCCGC(ctx context.Context, t test.Test, c cluster.Cluster) {
 
 	// How many times test repeats generate/cleanup cycles after initial one.
 	const cleanupRuns = 3
+	// How long to wait for data to be GCd during assert loop.
+	const gcRetryTimeout = 7 * time.Minute
 
 	c.Put(ctx, t.Cockroach(), "./cockroach")
 	s := install.MakeClusterSettings()
@@ -129,7 +131,7 @@ func runMVCCGC(ctx context.Context, t test.Test, c cluster.Cluster) {
 
 			t.L().Printf("partially deleted some data using tombstones")
 
-			assertRangesWithGCRetry(ctx, t, c, 5*time.Minute, m, func() error {
+			assertRangesWithGCRetry(ctx, t, c, gcRetryTimeout, m, func() error {
 				totals, rangeCount := collectTableMVCCStatsOrFatal(t, conn, m)
 				return checkRangesHaveNoRangeTombstones(totals, rangeCount)
 			})
@@ -152,7 +154,7 @@ func runMVCCGC(ctx context.Context, t test.Test, c cluster.Cluster) {
 			t.Fatal(err)
 		}
 
-		assertRangesWithGCRetry(ctx, t, c, 5*time.Minute, m, func() error {
+		assertRangesWithGCRetry(ctx, t, c, gcRetryTimeout, m, func() error {
 			totals, details := collectStatsAndConsistencyOrFail(t, conn, m)
 			return checkRangesConsistentAndHaveNoData(totals, details)
 		})