refactor: invoke functions from runtime

[eduardoboucas]

- Summary

This is the final PR for #2806. Unfortunately, I couldn't break it further down into smaller chunks because all the pieces are heavily interconnected.

I broke each change into its own commit and I'll add as much information as possible in comments, to make this as easy to review as possible.

[github-actions]

📊 Benchmark results

Comparing with 8bfdb2f

Package size: 330 MB

(no change)

^  329 MB  329 MB  329 MB  329 MB  329 MB  331 MB  331 MB  331 MB  331 MB  329 MB  329 MB  329 MB  330 MB 
│   ┌──┐    ┌──┐    ┌──┐    ┌──┐    ┌──┐    ┌──┐    ┌──┐    ┌──┐    ┌──┐    ┌──┐    ┌──┐    ┌──┐    ┌──┐  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
│   |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |  |    |▒▒|  
└───┴──┴────┴──┴────┴──┴────┴──┴────┴──┴────┴──┴────┴──┴────┴──┴────┴──┴────┴──┴────┴──┴────┴──┴────┴──┴──>
    T-12    T-11    T-10    T-9     T-8     T-7     T-6     T-5     T-4     T-3     T-2     T-1      T    

Legend

• T-30 (8bfdb2f): 330 MB
• T-29 (2e18003): 330 MB
• T-28 (fd3d2f7): 330 MB
• T-27 (d451cb3): 330 MB
• T-26 (c381072): 330 MB
• T-25 (537b760): 330 MB
• T-24 (172c955): 330 MB
• T-23 (259dd5f): 330 MB
• T-22 (9f41225): 330 MB
• T-21 (9f0ff3f): 329 MB
• T-20 (70ddcca): 329 MB
• T-19 (88df4e0): 329 MB
• T-18 (3897234): 329 MB
• T-17 (a378a98): 329 MB
• T-16 (39eaeb3): 329 MB
• T-15 (fd58db1): 329 MB
• T-14 (77c32cd): 329 MB
• T-13 (5ff47c9): 329 MB
• T-12 (129e434): 329 MB
• T-11 (f289cbd): 329 MB
• T-10 (9072cc9): 329 MB
• T-9 (202596e): 329 MB
• T-8 (1d975d6): 329 MB
• T-7 (11b2d1b): 331 MB
• T-6 (428d46c): 331 MB
• T-5 (ff7ff6a): 331 MB
• T-4 (41ff459): 331 MB
• T-3 (98c6667): 329 MB
• T-2 (4d0a89c): 329 MB
• T-1 (e1a091f): 329 MB
• T (current commit): 330 MB

[erezrokah]

Woo, @eduardoboucas this is SO MUCH BETTER.

I added some comments and also noticed an issue with netlify-lambda.
Since netlify-lambda populates the configured functions directory, getBuildFunction will manage to detect it only if it was executed an initial time before reaching that code.

To reproduce:

1. git clone https://github.com/erezrokah/netlify-build-reproductions
2. git checkout netlify_lambda
3. ntl dev
4. See that netlify-lambda is not detected

If you run npm run build a single time the detection works

We can fix this by moving the detection code earlier in the flow.

[erezrokah]

Thanks for the followup @eduardoboucas,

Added 2 clarifications to the review

[erezrokah]

🚀