Also package recursive jni_libs deps of android_apps as well as direct deps.

Previously, android_app targets for which a.shouldEmbedJnis(ctx) = true
(e.g. CtsSelinuxTargetSdk25TestCases) would need to specify all of their
recursive library dependencies, including for example libc++ when depending
on the platform libc++. This means unnecessary churn when we add a new
dependency to libc++ (e.g. libunwind [1]). To avoid the churn and allow
jni_libs clauses to be simplified, make the build system search for the
recursive dependencies and automatically include them.

This change allows us to remove code that was previously adding NDK libc++
as a special case, as it is now covered by the generic code.

Also fix some improper quoting that was exposed as a result of this change
causing more files to be packaged than before.

[1] https://android-review.googlesource.com/q/topic:%22libunwind-so%22

Bug: 144430859
Change-Id: I3d6fbcce75bc108a982eb7483992a4b202056339