Rather than constructing a new runtime._defer struct type at each
defer statement, we can use a single shared one. Also, by naming it
runtime._defer, we avoid emitting new runtime and DWARF type
descriptors in every package that contains a "defer" statement.
Shaves ~1kB off cmd/go.
Change-Id: I0bd819aec9f856546e684abf620e339a7555e73f
Reviewed-on: https://go-review.googlesource.com/c/go/+/521676 Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>