Pass classpath to d8

d8 requires the full classpath if --min-api requires default method
or try-with-resources desugaring.  Always pass the full classpath,
since it will already have been built to generate the input jar.

Bug: 116243313
Test: m checkbuild
Change-Id: Ib0c18873880697b7cf942e0548dd2c53ee5ad23c