[CMake][Fuchsia] Synchronize first and second stage builds

This reorders options between the first and second stage builds to make
them better lined up. The change also re-enables tests for first stage
which is useful e.g. for cross-compiling when we cannot run tests for
second stage directly (i.e. without emulation).

Differential Revision: https://reviews.llvm.org/D56652

llvm-svn: 351145