[bug] OutOfMemoryError bug in the workflow editor when iterating with loop over large number of items

[ivicac]

Sample workflow:

sample_10000.csv

{
    "label": "workflow10000",
    "description": "",
    "inputs": [],
    "triggers": [
        {
            "description": "",
            "label": "Manual",
            "name": "trigger_1",
            "type": "manual/v1/manual"
        }
    ],
    "tasks": [
        {
            "label": "Filesystem",
            "name": "filesystem_1",
            "parameters": {
                "filename": "/Volumes/Data/Users/ivicac2/Downloads/sample_10000.csv"
            },
            "type": "filesystem/v1/readFile",
            "metadata": {
                "ui": {
                    "dynamicPropertyTypes": {
                        "filename": "STRING"
                    }
                }
            }
        },
        {
            "label": "Filesystem",
            "name": "filesystem_2",
            "parameters": {
                "filename": "/Volumes/Data/Users/ivicac2/Downloads/result2.csv"
            },
            "type": "filesystem/v1/readFile",
            "metadata": {
                "ui": {
                    "dynamicPropertyTypes": {
                        "filename": "STRING"
                    }
                }
            }
        },
        {
            "label": "CSV File",
            "name": "csvFile_1",
            "parameters": {
                "delimiter": ",",
                "headerRow": true,
                "includeEmptyCells": false,
                "readAsString": false,
                "fileEntry": "${filesystem_1}"
            },
            "type": "csvFile/v1/read",
            "metadata": {
                "ui": {
                    "dynamicPropertyTypes": {
                        "fileEntry": "FILE_ENTRY"
                    }
                }
            }
        },
        {
            "label": "Loop",
            "name": "loop_1",
            "parameters": {
                "loopForever": false,
                "items": "${csvFile_1}",
                "iteratee": [
                    {
                        "label": "CSV File",
                        "name": "csvFile_2",
                        "parameters": {
                            "fileEntry": "${filesystem_2}",
                            "rows": [
                                "${loop_1.item}"
                            ]
                        },
                        "type": "csvFile/v1/append",
                        "metadata": {
                            "ui": {
                                "dynamicPropertyTypes": {
                                    "fileEntry": "FILE_ENTRY",
                                    "rows[0]": "OBJECT"
                                }
                            }
                        }
                    }
                ]
            },
            "type": "loop/v1",
            "metadata": {
                "ui": {
                    "dynamicPropertyTypes": {
                        "items": "ARRAY"
                    }
                }
            }
        },
        {
            "label": "Filesystem",
            "name": "filesystem_3",
            "parameters": {
                "fileEntry": "${filesystem_2}",
                "filename": "/Volumes/Data/Users/ivicac2/Downloads/result2.csv"
            },
            "type": "filesystem/v1/writeFile",
            "metadata": {
                "ui": {
                    "dynamicPropertyTypes": {
                        "fileEntry": "FILE_ENTRY",
                        "filename": "STRING"
                    }
                }
            }
        }
    ]
}

The solution is not to use SyncMessageBroker in JobSyncExecutor, but instead to create a new, simple, in-memory AsyncMessageBroker, then start the execution in the new thread an wait in the main thread until execution finishes to preserve sync behaviour