cmd/compile: another fix initializing blank fields in struct literal
CL 230121 fixed the bug that struct literal blank fields type array/struct
can not be initialized. But it still misses some cases when an expression
causes "candiscard(value)" return false. When these happen, we recursively
call fixedlit with "var_" set to "_", and hit the bug again.
To fix it, just making splitnode return "nblank" whenever "var_" is "nblank".
Fixes #38905
Change-Id: I281941b388acbd551a4d8ca1a235477f8d26fb6e
Reviewed-on: https://go-review.googlesource.com/c/go/+/232617
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com>