e2e: exec2: envoy binary version and tidying (#26558)

* e2e: update standalone envoy binary version

fix for:

> === FAIL: e2e/exec2 TestExec2/testCountdash (21.25s)
>     exec2_test.go:71:
> ...
> [warning][config] [./source/extensions/config_subscription/grpc/grpc_stream.h:155] DeltaAggregatedResources gRPC config stream to local_agent closed: 3, Envoy 1.29.4 is too old and is not supported by Consul

there's also this warning, but it doesn't seem so fatal:

> [warning][main] [source/server/server.cc:910] There is no configured limit to the number of allowed active downstream connections. Configure a limit in `envoy.resource_monitors.downstream_connections` resource monitor.

picked latest supported from latest consul (1.21.4):

```
$ curl -s localhost:8500/v1/agent/self | jq .xDS.SupportedProxies
{
  "envoy": [
    "1.34.1",
    "1.33.2",
    "1.32.5",
    "1.31.8"
  ]
}
```

* e2e: exec2: remove extraneous bits

 * reschedule: no reschedule for batch jobs
 * unveil: nomad paths get auto-unveiled with unveil_defaults
   https://github.com/hashicorp/nomad-driver-exec2/blob/v0.1.0/plugin/driver.go#L514-L522

e2e/exec2/input/countdash.hcl

@@ -30,10 +30,7 @@ job "countdash" {
               "${meta.connect.proxy_concurrency}",
               "--disable-hot-restart"
             ]
-            # TODO(shoenig) should not need NOMAD_ values once
-            # https://github.com/hashicorp/nomad-driver-exec2/issues/29 is
-            # fixed.
-            unveil = ["rx:/opt/bin", "rwc:/dev/shm", "r:${NOMAD_TASK_DIR}", "r:${NOMAD_SECRETS_DIR}"]
+            unveil = ["rx:/opt/bin", "rwc:/dev/shm"]
           }
 
           resources {
@@ -90,10 +87,7 @@ job "countdash" {
               "${meta.connect.proxy_concurrency}",
               "--disable-hot-restart"
             ]
-            # TODO(shoenig) should not need NOMAD_ values once
-            # https://github.com/hashicorp/nomad-driver-exec2/issues/29 is
-            # fixed.
-            unveil = ["rx:/opt/bin", "rwc:/dev/shm", "r:${NOMAD_TASK_DIR}", "r:${NOMAD_SECRETS_DIR}"]
+            unveil = ["rx:/opt/bin", "rwc:/dev/shm"]
           }
 
           resources {

e2e/exec2/input/env.hcl

@@ -12,11 +12,6 @@ job "env" {
   }
 
   group "group" {
-    reschedule {
-      attempts  = 0
-      unlimited = false
-    }
-
     restart {
       attempts = 0
       mode     = "fail"

e2e/exec2/input/secrets.hcl

@@ -13,11 +13,6 @@ job "secrets" {
   }
 
   group "group" {
-    reschedule {
-      attempts  = 0
-      unlimited = false
-    }
-
     restart {
       attempts = 0
       mode     = "fail"
@@ -31,11 +26,6 @@ job "secrets" {
       config {
         command = "cat"
         args    = ["${NOMAD_SECRETS_DIR}/nomad_token"]
-
-        # TODO(shoenig) should not need NOMAD_ values once
-        # https://github.com/hashicorp/nomad-driver-exec2/issues/29 is
-        # fixed.
-        unveil = ["r:${NOMAD_SECRETS_DIR}"]
       }
       resources {
         cpu    = 100
@@ -52,11 +42,6 @@ job "secrets" {
       config {
         command = "bash"
         args    = ["-c", "echo abc123 > ${NOMAD_SECRETS_DIR}/password.txt && cat ${NOMAD_SECRETS_DIR}/password.txt"]
-
-        # TODO(shoenig) should not need NOMAD_ values once
-        # https://github.com/hashicorp/nomad-driver-exec2/issues/29 is
-        # fixed.
-        unveil = ["rwc:${NOMAD_SECRETS_DIR}"]
       }
       resources {
         cpu    = 100

e2e/terraform/packer/ubuntu-jammy-amd64/setup.sh

@@ -132,7 +132,7 @@ sudo chmod +x ${NOMAD_PLUGIN_DIR}/nomad-driver-exec2
 
 # Envoy
 echo "Installing Envoy"
-sudo curl -s -S -L -o /opt/bin/envoy https://github.com/envoyproxy/envoy/releases/download/v1.29.4/envoy-1.29.4-linux-x86_64
+sudo curl -s -S -L -o /opt/bin/envoy https://github.com/envoyproxy/envoy/releases/download/v1.34.1/envoy-1.34.1-linux-x86_64
 sudo chmod +x /opt/bin/envoy
 
 echo "Updating boot parameters"