Ok, so it looks really similar than an issue in another topic, occurring also on High Sierra:
And indeed the JRE in use is not the bundled one, from your log it is:
Can I ask you to reinstall again SW in console mode (./install_sw4stm32_macos_64bits-v2.3.run -c) to see if any message helps us to locate the issue ?
Also the error message contains a code helping in that way:
Failed to install the bundled Java Runtime Environment into System Workbench for STM32 (error ERRORCODE) Application runtime will attempt to refer any already installed JRE
What is the value of ERRORCODE in your message ?