cmd/internal/obj/wasm, runtime: detect wasmexport call before runtime initialization
If a wasmexport function is called from the host before
initializing the Go Wasm module, currently it will likely fail
with a bounds error, because the uninitialized SP is 0, and any
SP decrement will make it out of bounds.
As at least some Wasm runtime doesn't call _initialize by default,
This error can be common. And the bounds error looks confusing to
the users. Therefore, we detect this case and emit a clearer error.
Fixes #71240.
Updates #65199.
Change-Id: I107095f08c76cdceb7781ab0304218eab7029ab6
Reviewed-on: https://go-review.googlesource.com/c/go/+/643115
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>