Enable `core:net` tests for FreeBSD

tests/core/net/test_core_net.odin

@@ -8,7 +8,7 @@
 
 	A test suite for `core:net`
 */
-//+build !netbsd !freebsd !openbsd
+//+build !netbsd !openbsd
 package test_core_net
 
 import "core:testing"