third_parth/llvm-7.0/BUILD.gn needed to update in order to
add additional required files as listed in chromium:961729.
Same needs to be done to the equivalent Android.bp file.

Bug: chromium:961729
Change-Id: I0afce6f8f4a8fa3b0d5e2001fe98c1686f410f78
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/31768Reviewed-by: Chris Forbes <chrisforbes@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Hernan Liatis <hliatis@google.com>