adb: Allow `adb rescue getprop`.

Which will dump all the allowed properties, similar to `adb shell
getprop`.

Bug: 134027350
Test: Run the command under rescue mode.
Change-Id: Id668224098006d71ee192c8c2bea5d791d2423c1
(cherry picked from commit 599eee1f3759bb9b1473b1bf2f46fb4ee1896fe2)
1 file changed