This allows the CLI to use `-hostlogging=filesystem,poll` instead of or in addition to multiple flags. This also makes the parameter loggers more debugable by using pointer receivers. When they are copied, the field names end up garbage in the debugger. Finally, this fixes a glitch where we used GOOS=js where we thought we were using WASI (in cmd tests). Signed-off-by: Adrian Cole <adrian@tetrate.io>