cmd/compile/internal/escape: additional constant and zero value tests and logging
This adds additional logging for the work that walk does to reduce
how often an interface conversion results in an allocation.
Also, as part of #71359, we will be updating how escape analysis and
walk handle basic literals, composite literals, and zero values,
so add some tests that uses this new logging.
By the end of our CL stack, we address all of these tests.
Updates #71359
Change-Id: I43fde8343d9aacaec1e05360417908014a86c8bd
Reviewed-on: https://go-review.googlesource.com/c/go/+/649076 Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Keith Randall <khr@google.com> Reviewed-by: David Chase <drchase@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
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