Ffmpeg trying to load js core file as wasm core: expected magic word

**Describe the bug**
fferr: wasm streaming compile failed: CompileError: WebAssembly.instantiateStreaming(): expected magic word 00 61 73 6d, found 0a 76 61 72 @+0

I'm using electron and I'm loading a custom core with webpack. The js core loads (see logs below) but when the wasm core tries to load, it seems to load the `ffmpeg-core.js` file instead of the `ffmpeg-core.wasm` file. The magic word it finds are the first 4 characters of the JS file.

**To Reproduce**

Ffmpeg 0.10.1
Custom core that uses less memory, nothing else. The core does work when loaded in a different project where it is simply on a public path.

This is how I load ffmpeg:
```
const ffmpeg = createFFmpeg({
corePath: require('file-loader!@/assets/ffmpeg/ffmpeg-core.js').default,
log: true
})
```

**Expected behavior**
Should be able to load the wasm core.

**Desktop (please complete the following information):**
- OS: [e.g. iOS] Windows
- Browser [e.g. chrome, safari] Chrome, Electron 11

**Additional context**
```
log.js:15 [info] use ffmpeg.wasm v0.10.1
09:05:07.036 ffmpeg.ts:18 info: load ffmpeg-core
09:05:07.036 log.js:15 [info] load ffmpeg-core
09:05:07.036 ffmpeg.ts:18 info: loading ffmpeg-core
09:05:07.036 log.js:15 [info] loading ffmpeg-core
09:05:07.040 ffmpeg.ts:18 info: fetch http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js
09:05:07.040 log.js:15 [info] fetch http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js
09:05:07.044 ffmpeg.ts:18 info: http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js file size = 107813 bytes
09:05:07.044 log.js:15 [info] http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js file size = 107813 bytes
09:05:07.045 ffmpeg.ts:18 info: http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js blob URL = blob:http://localhost:3000/22f60f05-b453-4ccc-93b5-86ea33c3b71a
09:05:07.045 log.js:15 [info] http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js blob URL = blob:http://localhost:3000/22f60f05-b453-4ccc-93b5-86ea33c3b71a
09:05:07.045 ffmpeg.ts:18 info: fetch http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js
09:05:07.045 log.js:15 [info] fetch http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js
09:05:07.048 ffmpeg.ts:18 info: http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js file size = 107813 bytes
09:05:07.048 log.js:15 [info] http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js file size = 107813 bytes
09:05:07.049 ffmpeg.ts:18 info: http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js blob URL = blob:http://localhost:3000/48e54a2e-90a3-415d-8bf3-f00ad0d3b42e
09:05:07.049 log.js:15 [info] http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js blob URL = blob:http://localhost:3000/48e54a2e-90a3-415d-8bf3-f00ad0d3b42e
09:05:07.049 ffmpeg.ts:18 info: fetch http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js
09:05:07.049 log.js:15 [info] fetch http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js
09:05:07.054 ffmpeg.ts:18 info: http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js file size = 107813 bytes
09:05:07.054 log.js:15 [info] http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js file size = 107813 bytes
09:05:07.054 ffmpeg.ts:18 info: http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js blob URL = blob:http://localhost:3000/90fd5a04-f78e-48b5-8fcb-720adbdfa6b5
09:05:07.054 log.js:15 [info] http://localhost:3000/7e6e51a3b3b0929ab8f8414204599707.js blob URL = blob:http://localhost:3000/90fd5a04-f78e-48b5-8fcb-720adbdfa6b5
09:05:07.061 ffmpeg.ts:18 info: ffmpeg-core.js script loaded
09:05:07.061 log.js:15 [info] ffmpeg-core.js script loaded
09:05:07.071 ffmpeg.ts:18 fferr: wasm streaming compile failed: CompileError: WebAssembly.instantiateStreaming(): expected magic word 00 61 73 6d, found 0a 76 61 72 @+0
09:05:07.071 log.js:15 [fferr] wasm streaming compile failed: CompileError: WebAssembly.instantiateStreaming(): expected magic word 00 61 73 6d, found 0a 76 61 72 @+0
09:05:07.071 ffmpeg.ts:18 fferr: falling back to ArrayBuffer instantiation
09:05:07.072 log.js:15 [fferr] falling back to ArrayBuffer instantiation
09:05:07.073 ffmpeg.ts:18 fferr: failed to asynchronously prepare wasm: CompileError: WebAssembly.instantiate(): expected magic word 00 61 73 6d, found 0a 76 61 72 @+0
09:05:07.073 log.js:15 [fferr] failed to asynchronously prepare wasm: CompileError: WebAssembly.instantiate(): expected magic word 00 61 73 6d, found 0a 76 61 72 @+0
09:05:07.073 ffmpeg.ts:18 fferr: CompileError: WebAssembly.instantiate(): expected magic word 00 61 73 6d, found 0a 76 61 72 @+0
09:05:07.074
```