Introduce ApplicationInfo.getAllApkPaths().

Add an internal method to ApplicationInfo to get all APK files that may
be required by an application. This moves assumptions about how apps are
constructed out of Zygote.allowAppFilesAcrossFork and into a more
appropriate place where it can be shared.

Bug: 124116212
Test: atest android.webkit.cts.WebViewTest
Change-Id: I79add98c4922c4f97263bff78cf808bc38274755