Chunk contents are lost with some values of `output.libraryTarget`

Issue description

When using global, window, this, commonjs, commonjs2, or assign as output.libraryTarget, chunk contents are not displayed in report. var, umd, 'amd', 'amd-require', 'system', and 'jsonp' work OK.

Technical info

System:
    OS: macOS 10.15.6
    CPU: (16) x64 Intel(R) Core(TM) i9-9980HK CPU @ 2.40GHz
    Memory: 1.35 GB / 32.00 GB
    Shell: 5.7.1 - /bin/zsh
  Binaries:
    Node: 12.18.2 - ~/n/bin/node
    Yarn: 1.22.4 - /usr/local/bin/yarn
    npm: 6.14.5 - ~/n/bin/npm
    Watchman: 4.9.0 - /usr/local/bin/watchman
  npmPackages:
    webpack: ^4.43.0 => 4.43.0 
    webpack-bundle-analyzer: ^3.8.0 => 3.8.0 
    webpack-cli: ^3.3.12 => 3.3.12 

Reproduction

https://github.com/Hypnosphi/webpack-bundle-analyzer-repro

Expected

Actual

Start with the linked webpack-bundle-analyzer reproduction and compare reports for the listed output.libraryTarget values, especially global, window, this, commonjs, commonjs2, and assign versus the working targets. Trace how chunk contents are collected and displayed, then verify that the affected targets show chunk contents in the report without regressing the working cases.