Build recovery variant of the dynamic linker

In order to support shared libraries in the recovery mode, the dynamic
linker is now built with recovery_available: true option.

In addition, a few more modules (such as libasync, etc.) are also marked
as recovery_available: true as they are transitive dependencies of the
dynamic linker.

Bug: 63673171
Test: `adb reboot recovery; adb devices` shows the device ID
Test: `adb root && adb shell` and then
$ lsof -p `pidof adbd` shows that libm.so, libc.so, etc. are loaded from
the /lib directory.

Change-Id: Idd981d8cf25568a85b24032cf78e50adfd5f4a7f