runtime: remove enable_swap option

`enable_swap` option was added long time ago to add
`-realtime mlock=off` to the QEMU's command line.
Kata now supports QEMU 6, `-realtime` option has been deprecated and
`mlock=on` is causing unexpected behaviors in kata.
This patch removes support for `enable_swap`, `-realtime` and `mlock=`
since they are causing bugs in kata.

Signed-off-by: Julio Montes <julio.montes@intel.com>

src/runtime/pkg/katautils/config_test.go

@@ -155,7 +155,6 @@ func createAllRuntimeConfigFiles(dir, hypervisor string) (config testRuntimeConf
 		DisableBlockDeviceUse: disableBlockDevice,
 		BlockDeviceDriver:     defaultBlockDeviceDriver,
 		DefaultBridges:        defaultBridgesCount,
-		Mlock:                 !defaultEnableSwap,
 		EnableIOThreads:       enableIOThreads,
 		HotplugVFIOOnRootBus:  hotplugVFIOOnRootBus,
 		PCIeRootPort:          pcieRootPort,
@@ -563,7 +562,6 @@ func TestMinimalRuntimeConfig(t *testing.T) {
 		MemorySize:            defaultMemSize,
 		DisableBlockDeviceUse: defaultDisableBlockDeviceUse,
 		DefaultBridges:        defaultBridgesCount,
-		Mlock:                 !defaultEnableSwap,
 		BlockDeviceDriver:     defaultBlockDeviceDriver,
 		Msize9p:               defaultMsize9p,
 		GuestHookPath:         defaultGuestHookPath,