wasi: remove --no-threads flag as no longer in LLVM 11 linker

Signed-off-by: deadprogram <ron@hybridgroup.com>

targets/wasi.json

@@ -12,7 +12,6 @@
 	],
 	"ldflags": [
 		"--allow-undefined",
-		"--no-threads",
 		"--stack-first",
 		"--export-dynamic",
 		"--no-demangle",