[test] Add new test experiment with long running concurrent blocks

test/experiments/username/username/triangle/1/triangle_sleep.json

+{
+  "analyzers": {
+    "analysis": {
+      "algorithm": "{{ user.username }}/integers_echo_analyzer/1",
+      "inputs": {
+        "in_data": "in"
+      }
+    }
+  },
+  "blocks": {
+    "echo1": {
+      "algorithm": "{{ user.username }}/integers_echo_sleep/1",
+      "inputs": {
+        "in_data": "in"
+      },
+      "outputs": {
+        "out_data": "out"
+      }
+    },
+    "echo2": {
+      "algorithm": "{{ user.username }}/integers_echo_sleep/1",
+      "inputs": {
+        "in_data": "in"
+      },
+      "outputs": {
+        "out_data": "out"
+      }
+    },
+    "echo3": {
+      "algorithm": "{{ user.username }}/integers_echo_ignore/1",
+      "inputs": {
+        "in_data": "in",
+        "in_data2": "in2"
+      },
+      "outputs": {
+        "out_data": "out"
+      }
+    }
+  },
+  "datasets": {
+    "set": {
+      "database": "simple/1",
+      "protocol": "protocol",
+      "set": "set"
+    },
+    "set2": {
+      "database": "simple/1",
+      "protocol": "protocol",
+      "set": "set2"
+    }
+  },
+  "globals": {
+    "queue": "{{ queue }}",
+    "environment": {
+      "name": "{{ environment.name }}",
+      "version": "{{ environment.version }}"
+    }
+  }
+}