test: remove package-wide import assumptions

test/wcc/data/r815_int_printf/case.ww

@@ -1,6 +1,5 @@
 //ww:run-exit 54
 package main;
-import os;
 import fmt;
 import io;
 export fn main() i32 = { let buf: [16]u8; let x: int = 42; let v: str = ""; match (fmt.bsprintf(buf[0:16], "{}", x)) { case let s: str => { v = s; }; case io.error => { return 91; }; }; if (v.len != 2) { return 92; }; if (v[0] != 52u8 || v[1] != 50u8) { return 93; }; return 54; };