[roll] Roll fuchsia [golang] Only the go_build() invocation should dep on the library, not the host test

As the dependency on the go_library() is handled by the go_build()
target, there's no need to create a duplicate dependency edge from
the host_test() as well.  Especially since the go_build() target
will restat its output and host_test() cannot.

The result here is that if a change to a file in a go_library()
results in no change to the test binary, the build will not
dirty any downstream targets after ninja restats the test binary
and finds that it's unchanged.

This can truncate the build after only a few actions, instead of
thousands.

This also shifts how deps which are host_test_data() need to be
handled in the case of variant toolchains.  Those may need to
be explicitly included using the base toolchain instead of the
variant toolchain (the implicitly default), if those test deps
are coming through the go_binary() or go_library() targets and
not through the test target itself.

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/954427
Original-Revision: 56eab360511e99f83547f8d75668f942053aed82
GitOrigin-RevId: 2f8b81a700e7a9fab72e654af2e48f7191a8c35b
Change-Id: I670f2cc1b9c5c297cac0bebe4a118c7ee1addf20