run: Bump default RAM size from 128 MB to 256 MB

Kernel/run

@@ -13,7 +13,7 @@ cd "$script_path"
 
 [ -z "$SERENITY_KERNEL_CMDLINE" ] && SERENITY_KERNEL_CMDLINE="hello"
 
-[ -z "$SERENITY_RAM_SIZE" ] && SERENITY_RAM_SIZE=128M
+[ -z "$SERENITY_RAM_SIZE" ] && SERENITY_RAM_SIZE=256M
 
 [ -z "$SERENITY_COMMON_QEMU_ARGS" ] && SERENITY_COMMON_QEMU_ARGS="
 $SERENITY_EXTRA_QEMU_ARGS