Meta: Bump default RAM size to 512MB

Now that we commit memory, we need a lot more physical memory. Physical
memory requirements can be reduced again once we have memory swapping,
which allows the swap area/file to be counted against memory that can
be committed.

Meta/run.sh

@@ -18,7 +18,7 @@ die() {
 
 [ -z "$SERENITY_KERNEL_CMDLINE" ] && SERENITY_KERNEL_CMDLINE="hello"
 
-[ -z "$SERENITY_RAM_SIZE" ] && SERENITY_RAM_SIZE=256M
+[ -z "$SERENITY_RAM_SIZE" ] && SERENITY_RAM_SIZE=512M
 
 [ -z "$SERENITY_QEMU_CPU" ] && SERENITY_QEMU_CPU="max"