[Bug go/89321] cross build with riscv64 gccgo compilation failed due to assert in constructor_expression

[sean.wang at wdc dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89321

--- Comment #4 from sean.wang at wdc dot com ---
The assert it reached was this I think:
 gcc_assert(field == NULL_TREE);

Thanks, Ian. It is helpful. I think I found a way to reproduce this issue on a
smaller set of code. Will provide an example once I have everything stubbed
out.