bpo-40280: Emscripten has no support for subprocesses (GH-29872)

bpo-40280: Emscripten has no support for subprocesses (GH-29872) · python/cpython@cb2b3c8

Original file line number	Diff line number	Diff line change
`@@ -607,7 +607,10 @@ def _syscmd_file(target, default=''):`
`607`	`607`	`# XXX Others too ?`
`608`	`608`	`return default`
`609`	`609`
`610`		`-import subprocess`
	`610`	`+try:`
	`611`	`+import subprocess`
	`612`	`+except ImportError:`
	`613`	`+return default`
`611`	`614`	`target = _follow_symlinks(target)`
`612`	`615`	`# "file" output is locale dependent: force the usage of the C locale`
`613`	`616`	`# to get deterministic behavior.`
`@@ -746,7 +749,10 @@ def from_subprocess():`
`746`	`749`	`"""`
`747`	`750`	Fall back to `uname -p`
`748`	`751`	`"""`
`749`		`-import subprocess`
	`752`	`+try:`
	`753`	`+import subprocess`
	`754`	`+except ImportError:`
	`755`	`+return None`
`750`	`756`	`try:`
`751`	`757`	`return subprocess.check_output(`
`752`	`758`	`['uname', '-p'],`