compiler: initialize saw_send_stmt locals

The C++ compiler wasn't warning because we take their address.

Fixes golang/go#43252

Change-Id: I52f6dc4a66a4dc33d41eb39334432a729c4a885f
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/279752
Trust: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
1 file changed