gatsby: gatsby-plugin-styled-jsx-postcss causes new gatsby version to hang

Description

When using gatsby-plugin-styled-jsx-postcss and a newer version of gatsbyjs, gatsby gets stuck at “Building development module”. This previously worked for gatsby 2.0.75, but now hangs with gatsby 2.19.23.

Steps to reproduce

gatsby new postcss-bug https://github.com/edmcman/gatsby-starter-default
cd postcss-bug
gatsby develop

Expected result

Gatsby starts a development server within a reasonable amount of time (fewer than 5 minutes)

Actual result

Gatsby seems to get stuck forever at “Building development bundle”.

Environment

  System:
    OS: macOS 10.15.3
    CPU: (4) x64 Intel(R) Core(TM) i7-5557U CPU @ 3.10GHz
    Shell: 3.2.57 - /bin/bash
  Binaries:
    Node: 13.8.0 - /opt/local/bin/node
    npm: 6.13.7 - /opt/local/bin/npm
  Languages:
    Python: 3.7.6 - /opt/local/bin/python
  Browsers:
    Chrome: 80.0.3987.122
    Firefox: 57.0.4
    Safari: 13.0.5
  npmPackages:
    gatsby: ^2.19.7 => 2.19.23
    gatsby-image: ^2.2.39 => 2.2.41
    gatsby-plugin-manifest: ^2.2.39 => 2.2.42
    gatsby-plugin-offline: ^3.0.32 => 3.0.35
    gatsby-plugin-react-helmet: ^3.1.21 => 3.1.22
    gatsby-plugin-sharp: ^2.4.3 => 2.4.5
    gatsby-plugin-styled-jsx: ^3.1.19 => 3.1.19
    gatsby-plugin-styled-jsx-postcss: ^2.0.2 => 2.0.2
    gatsby-source-filesystem: ^2.1.46 => 2.1.48
    gatsby-transformer-sharp: ^2.3.13 => 2.3.16
  npmGlobalPackages:
    gatsby-cli: 2.9.0
    gatsby: 2.0.91