Revert^2 "Use libdexfile external API in libunwindstack."

This reverts commit cacf5bf6.

Reason for revert: Re-apply with proper fix for VNDK visibility on marlin and sailfish.

Test: Manual repro of http://b/121110092#comment1 on reported branch
Test: atest CtsRenderscriptTestCases
Test: mmma system/core/{libunwindstack,libbacktrace}, run host gtests
Test: Make image, flash, and reboot device.
Test: Forrest cts/art/gce-all: https://android-build.googleplex.com/builds/forrest/run/L00300000240828791
Test: Forrest cts/bionic/gce-all: https://android-build.googleplex.com/builds/forrest/run/L05600000240682947 (shows 27/2958 failed, but it doesn't pass on Blackbox either: http://screen/xbjioEf6UgR)
Test: Forrest cts/renderscript/gce-all: https://android-build.googleplex.com/builds/forrest/run/L66200000240680523
Bug: 119632407
Change-Id: I601aa97eac8127e30d753405f8bc1fc4ae7f849f