Fix dependencies through symlinks

Now that ninja uses lstat so that we can get the mtime of the symlink
itself, it's safe to use a real input here rather than an order only
input. This matches how our other install rules work for host files.
Symlinks should be quick to recreate, so I'm not copying the logic to do
order-only dependencies for the device.

Bug: 128577186
Bug: 145278193
Bug: 135515543
Test: m out/target/product/walleye/apex/com.android.art.debug/javalib/arm/boot.art
      rm out/soong/host/linux-x86/bin/dex2oatd64
      m out/target/product/walleye/apex/com.android.art.debug/javalib/arm/boot.art

Change-Id: Ief5ec752ce0d0216aeecd8e904afc59f3f08ed7d