Test loader doesn't work : Critical dependency: the request of a dependency is an expression

With NodeJS v16.13.0 on Windows
```
$ npm run build && npx webpack --config test/config/javascript-obfuscator-loader.config.js --stats-error-details

> webpack-obfuscator@3.5.1 build
> npx tsc

asset index.js 1.13 KiB [emitted] [minimized] (name: index) 1 related asset
asset index-excluded.js 1.02 KiB [emitted] [minimized] (name: index-excluded) 1 related asset
runtime modules 211 bytes 2 modules
cacheable modules 2.78 KiB
./test/input/index.js 1.41 KiB [built] [code generated]
./test/input/index-excluded.js 245 bytes [built] [code generated]
./test/input/nested.js 1.13 KiB [built] [code generated]
./test/input/ sync 160 bytes [built] [code generated]

WARNING in ./test/input/index.js 1:1127-1152
Critical dependency: the request of a dependency is an expression
at CommonJsRequireContextDependency.getWarnings (xxx\webpack-obfuscator\node_modules\webpack\lib\dependencies\ContextDependency.js:91:18)
at Compilation.reportDependencyErrorsAndWarnings (xxx\webpack-obfuscator\node_modules\webpack\lib\Compilation.js:3131:24)
at xxx\webpack-obfuscator\node_modules\webpack\lib\Compilation.js:2728:28
at _next2 (eval at create (xxx\webpack-obfuscator\node_modules\tapable\lib\HookCodeFactory.js:33:10), :25:1)
at eval (eval at create (xxx\webpack-obfuscator\node_modules\tapable\lib\HookCodeFactory.js:33:10), :52:1)
at xxx\webpack-obfuscator\node_modules\webpack\lib\FlagDependencyExportsPlugin.js:385:11
at xxx\webpack-obfuscator\node_modules\neo-async\async.js:2830:7
at Object.each (xxx\webpack-obfuscator\node_modules\neo-async\async.js:2850:39)
at xxx\webpack-obfuscator\node_modules\webpack\lib\FlagDependencyExportsPlugin.js:361:18
at xxx\webpack-obfuscator\node_modules\neo-async\async.js:2830:7
```

使用 test/config/javascript-obfuscator-loader.config.js 重现报告中的命令，并检查 test/input/index.js、test/input/index-excluded.js 和 test/input/nested.js。确定发出的 critical-dependency 警告是否就是 loader 失败，然后根据该结果验证预期的 loader 测试行为并记录完成情况。

由索引模型根据 Issue 内容生成。