Revert "Split Rust crate builds into compile and link phases."

This reverts commit e7c71c34.
The intermediates created by the separated rust compile steps are very
large, on the order of 60GB.  This is more than CI can support for now,
revert the split into compile and link phases.  This comes at the expense
of incremental build time, especially when modifying C/C++ sources that
are dependencies of rust modules.

Bug: 293349612
Test: builds
Change-Id: I81169e7d0727330c8de5e7688dcdc87fe7b8d3b5