This change also fixes the corresponding code in go/packages, which was
actually not filling in the TypesSizes if the bit was set.
Change-Id: I2d5a849045768a81c94218eb41da2faec26189a3
Reviewed-on: https://go-review.googlesource.com/c/tools/+/170010
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>