behavior: add test coverage for slicing zero length array field of struct

Closes ziglang#11787

Author: wooster0

lib/std/segmented_list.zig

@@ -412,10 +412,7 @@ pub fn SegmentedList(comptime T: type, comptime prealloc_item_count: usize) type
 }
 
 test "SegmentedList basic usage" {
-    if (false) {
-        // https://github.com/ziglang/zig/issues/11787
-        try testSegmentedList(0);
-    }
+    try testSegmentedList(0);
     try testSegmentedList(1);
     try testSegmentedList(2);
     try testSegmentedList(4);

test/behavior/slicing_zero_length_array_field_of_struct.zig

@@ -0,0 +1,10 @@
+pub export fn entry() void {
+    const S = struct {
+        a: [0]usize,
+        fn foo(self: *@This(), start: usize, end: usize) []usize {
+            return self.a[start..end];
+        }
+    };
+    var s: S = undefined;
+    _ = s.foo(0, 0);
+}