Fix toybox_vendor dependencies on libselinux_vendor.

Fix toybox_vendor dependencies on libselinux_vendor.

toybox_vendor now links to other libraries as shared libraries.
This allows toybox_vendor to use the "vendor" version of these libraries
(in particular, liblog and libselinx_vendor).

Test: mma -j
Test: m -j, flash, boots
Test: `adb shell /vendor/bin/restorecon /dev/null` shows error message
Test: `adb shell /vendor/bin/getprop -Z' shows error message
Test: mma -j BOARD_VNDK_VERSION=current

Bug: 62886649
Change-Id: If01094b71ef7e99b5756b851132de643660a1e2c