Handle Python long ints as Javascript floats

Fix benchmarks in light of recent changes

Fix patch against library_lz4.js

Testing of build artifacts under a custom path

MAINT: Lint all the things

Upgrade to emscripten 1.38.12

Use constant hiwire ids for singleton values

No need to copy bound method name

Refactoring common functions under pyodide_build

Use "BINARYEN_TRAP_MODE='clamp'"

Disable sigaction and utimensat syscalls

This reverts commit 3ff79f6a.