itest: increase retry count and max backoff timeout for proof courier

Allow more retries and a longer maximum backoff duration in the default
config to give proof transfers more time and reduce flakiness.

Update itest timeout to scale with the new maximum backoff duration.

Author: ffranr

itest/send_test.go

@@ -759,8 +759,7 @@ func testReattemptFailedSendHashmailCourier(t *harnessTest) {
 	expectedEventCount := nodeBackoffCfg.NumTries - 1
 
 	// Context timeout scales with expected number of events.
-	timeout := time.Duration(expectedEventCount) *
-		defaultProofTransferReceiverAckTimeout
+	timeout := time.Duration(expectedEventCount) * nodeBackoffCfg.MaxBackoff
 
 	// Allow for some margin for the operations that aren't pure
 	// waiting on the receiver ACK.
@@ -867,8 +866,7 @@ func testReattemptProofTransferOnTapdRestart(t *harnessTest) {
 	expectedEventCount := nodeBackoffCfg.NumTries - 1
 
 	// Context timeout scales with expected number of events.
-	timeout := time.Duration(expectedEventCount) *
-		defaultProofTransferReceiverAckTimeout
+	timeout := time.Duration(expectedEventCount) * nodeBackoffCfg.MaxBackoff
 
 	// Allow for some margin for the operations that aren't pure waiting on
 	// the receiver ACK.
@@ -1028,8 +1026,7 @@ func testReattemptFailedSendUniCourier(t *harnessTest) {
 	expectedEventCount := nodeBackoffCfg.NumTries - 1
 
 	// Context timeout scales with expected number of events.
-	timeout := time.Duration(expectedEventCount) *
-		defaultProofTransferReceiverAckTimeout
+	timeout := time.Duration(expectedEventCount) * nodeBackoffCfg.MaxBackoff
 
 	// Allow for some margin for the operations that aren't pure waiting on
 	// the receiver ACK.

itest/tapd_harness.go

@@ -57,19 +57,19 @@ var (
 	// for sending proofs with the hashmail courier.
 	defaultHashmailBackoffConfig = proof.BackoffCfg{
 		BackoffResetWait: time.Second,
-		NumTries:         5,
+		NumTries:         10,
 		InitialBackoff:   300 * time.Millisecond,
-		MaxBackoff:       600 * time.Millisecond,
+		MaxBackoff:       2 * time.Second,
 	}
 
 	// defaultUniverseRpcBackoffConfig is the default backoff config we'll
 	// use for sending proofs with the universe RPC courier.
 	defaultUniverseRpcBackoffConfig = proof.BackoffCfg{
 		SkipInitDelay:    true,
 		BackoffResetWait: time.Second,
-		NumTries:         5,
+		NumTries:         10,
 		InitialBackoff:   300 * time.Millisecond,
-		MaxBackoff:       600 * time.Millisecond,
+		MaxBackoff:       2 * time.Second,
 	}
 
 	// defaultProofRetrievalDelay is the default delay we'll use for the