When installing local "dev" extensions that provide tree-sitter
grammars, compiling the parser can be quite intensive[^anecdote]. This
PR changes the logic to only compile the parser if the WASM object
doesn't exist or the source files are newer than the object (just like
`make(1)` would do).

[^anecdote]: The tree-sitter parser for LLVM IR takes >10 minutes to
compile and uses 20 GB of memory on my laptop.

Release Notes:

- N/A

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Co-authored-by: Finn Evers <finn.evers@outlook.de>