Exclude adb socket for AlwaysOnVpn tests

If adb over network is used, AlwaysOnVpn tests destroy adb socket and stop due to adb disconnect.

Test: atest MixedManagedProfileOwnerTest#testAlwaysOnVpn \
            MixedManagedProfileOwnerTest#testAlwaysOnVpnLockDown \
            MixedManagedProfileOwnerTest#testAlwaysOnVpnPackageUninstalled \
            MixedManagedProfileOwnerTest#testAlwaysOnVpnUnsupportedPackage \
            MixedManagedProfileOwnerTest#testAlwaysOnVpnUnsupportedPackageReplaced
Test: atest MixedDeviceOwnerTest#testAlwaysOnVpn \
            MixedDeviceOwnerTest#testAlwaysOnVpnLockDown \
            MixedDeviceOwnerTest#testAlwaysOnVpnPackageUninstalled \
            MixedDeviceOwnerTest#testAlwaysOnVpnUnsupportedPackage \
            MixedDeviceOwnerTest#testAlwaysOnVpnUnsupportedPackageReplaced
Bug: 120682119
Bug: 120684498

Change-Id: Ieca6ce9c947301bcc63aa31614b473926b5492cf
7 files changed