test(e2e-single): extend SSH wait budget to 3m on slow boot paths

CI run 26034322018 timed out Phase5a_ii_SSH (60s budget) and
Phase8b_VPCSubnetE2E (2m budget) on the TCP-port-open poll while
sshd was still finishing pam/cloud-init. Bump all four wait sites
to 3m as a stop-gap:

- single/instance_test.go phase5aii_SSHProbe
- single/lifecycle_test.go waitForSSHReady (Phase 7b/7c/7c-pre)
- single/vpc_test.go phase8b_VPCSubnetE2E
- single/natgw_test.go phase8d bastion SSH wait

Proper fix tracked under mulga-siv-101 (hoist a harness.WaitForSSH
that probes the actual handshake, not just tcp/22 reachability).

tests/e2e/single/instance_test.go

@@ -136,7 +136,7 @@ func phase5aii_SSHProbe(t *testing.T, fix *Fixture) {
 		}
 		_ = conn.Close()
 		return true
-	}, 60*time.Second, 2*time.Second, "SSH port "+addr+" never became reachable")
+	}, 3*time.Minute, 2*time.Second, "SSH port "+addr+" never became reachable")
 
 	tgt := harness.SSHTarget{User: "ec2-user", Host: host, Port: port, KeyPath: fix.KeyPath}
 

tests/e2e/single/lifecycle_test.go

@@ -367,5 +367,5 @@ func waitForSSHReady(t *testing.T, host string, port int) {
 		}
 		_ = conn.Close()
 		return true
-	}, 60*time.Second, 2*time.Second, fmt.Sprintf("SSH port %s never became reachable", addr))
+	}, 3*time.Minute, 2*time.Second, fmt.Sprintf("SSH port %s never became reachable", addr))
 }

tests/e2e/single/natgw_test.go

@@ -140,7 +140,7 @@ func phase8d_NATGateway(t *testing.T, fix *Fixture) {
 		}
 		_ = conn.Close()
 		return true
-	}, 2*time.Minute, 2*time.Second, "bastion SSH never reachable")
+	}, 3*time.Minute, 2*time.Second, "bastion SSH never reachable")
 
 	bastionTgt := harness.SSHTarget{User: "ec2-user", Host: bastionPubIP, Port: 22, KeyPath: fix.KeyPath}
 

tests/e2e/single/vpc_test.go

@@ -234,7 +234,7 @@ func phase8b_VPCSubnetE2E(t *testing.T, fix *Fixture) {
 		}
 		_ = conn.Close()
 		return true
-	}, 2*time.Minute, 2*time.Second, "SSH on "+addr+" never became reachable")
+	}, 3*time.Minute, 2*time.Second, "SSH on "+addr+" never became reachable")
 
 	tgt := harness.SSHTarget{User: "ec2-user", Host: pubIP, Port: 22, KeyPath: fix.KeyPath}