cmd/compile/internal/noder: TestUnifiedCompare fails with changes in dev.fuzz branch

[jayconrod]

I noticed this when merging master into dev.fuzz, originally at CL 347232 PS1. See test log. The error is:

--- FAIL: TestUnifiedCompare (29.96s)
    --- FAIL: TestUnifiedCompare/linux/amd64 (29.95s)
        unified_test.go:121: running /workdir/go/bin/go list -e -export -json -gcflags=all=-d=unified=0 -d=inlfuncswithclosures=0 -d=unifiedquirks=1 -G=0 -- std
        unified_test.go:121: running /workdir/go/bin/go list -e -export -json -gcflags=all=-d=unified=1 -d=inlfuncswithclosures=0 -d=unifiedquirks=1 -G=0 -- std
        unified_test.go:95: package "testing/internal/testdeps": compile output differs
FAIL
FAIL	cmd/compile/internal/noder	29.971s

We use type aliases in testing/internal/testdeps to avoid an import cycle between testing and internal tests of internal/fuzz and the packages it depends on. That may be tripping something here.

Per discussion with @mdempsky, it sounds like this may be an overly strict test. We'll skip it on dev.fuzz for now, but we won't merge dev.fuzz into master before the test is fixed.