Reinstate NBC.

core/runtime/core_builtin.odin

@@ -425,7 +425,7 @@ insert_at_elems :: proc(array: ^$T/[dynamic]$E, index: int, args: ..E, loc := #c
 }
 
 @builtin
-insert_at_elem_string :: proc(array: ^$T/[dynamic]$E/u8, index: int, arg: string, loc := #caller_location) -> (ok: bool) {
+insert_at_elem_string :: proc(array: ^$T/[dynamic]$E/u8, index: int, arg: string, loc := #caller_location) -> (ok: bool) #no_bounds_check {
 	if array == nil {
 		return
 	}