Revert "go/analysis: add Sizes that matches gc size computations"

This reverts CL 501495 (commit 5aa6acb).

Reason for revert: Per internal discussion, we should fix go/types.
                   See issue #61035.

Change-Id: Ia63587af701b864acc1b43939954eae76572a407
Reviewed-on: https://go-review.googlesource.com/c/tools/+/506596
Reviewed-by: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Robert Griesemer <gri@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>

go/analysis/unitchecker/unitchecker.go

@@ -218,7 +218,7 @@ func run(fset *token.FileSet, cfg *Config, analyzers []*analysis.Analyzer) ([]re
 	})
 	tc := &types.Config{
 		Importer: importer,
-		Sizes:    sizesFor("gc", build.Default.GOARCH), // assume gccgo ≡ gc?
+		Sizes:    types.SizesFor("gc", build.Default.GOARCH), // assume gccgo ≡ gc?
 	}
 	info := &types.Info{
 		Types:      make(map[ast.Expr]types.TypeAndValue),