Test cross-package references involving assembly files.

-- go.mod --
module example.com
go 1.24

-- lib/lib.go --
package lib

func Helper() int { return 42 } //@loc(defHelper, "Helper"), refs("Helper", defHelper, goCallHelper, asmCallHelper)

-- caller/caller.go --
package caller

import "example.com/lib"

func Use() {
    lib.Helper() //@loc(goCallHelper, "Helper")
}

-- caller/impl.s --
TEXT ·Wrapper(SB), $0-0
    CALL example·com∕lib·Helper(SB) //@loc(asmCallHelper, "example·com∕lib·Helper"), refs("Helper", defHelper, goCallHelper, asmCallHelper)
    RET
