enforce buff channel size > 0 (#2952)

* fix(stdlib): enforce BufferedChannel size > 0 and add regression test

* chore(repo): ignore cmake/test artifacts

* Formatting

---------

Co-authored-by: Christoffer Lerno <christoffer.lerno@gmail.com>

test/test_suite/stdlib/channels.c3

@@ -0,0 +1,8 @@
+import std::thread;
+
+fn int main()
+{
+	BufferedChannel{int} c;
+	c.init(mem, 0)!!; // #error: @require "size > 0" violated: 'channel size must be > 0'.
+	return 0;
+}