Add tests for update_binary_command().

Expose update_binary_command() through private/install.h for testing
purpose.

Also make minor clean-ups to install.cpp: a) adding more verbose logging
on ExtractToMemory failures; b) update_binary_command() taking
std::string instead of const char*; c) moving a few macro and global
constants into update_binary_command().

Bug: 37300957
Test: recovery_component_test on marlin
Test: Build new recovery and adb sideload on angler and sailfish.
Change-Id: Ib2d9068af3fee038f01c90940ccaeb0a7da374fc