Remove vndk-vtable-dumper

This commit removes `vndk-vtable-dumper` so that the number of users of
`external/llvm` can be reduced.  Removing this should be fine because
VTS test cases now have their own vtable dumper written in Python[1].

[1] https://android.googlesource.com/platform/test/vts/+/a94a81126024913960e0d2c35d7117f7fa80b8bc

Bug: 66510313
Test: n/a
Change-Id: Ic46816f7faeb7eb859d47d2942806cb1be63a455