perf: replace std.debug.assert with inlined version

See doc comment in `quirks.zig` for reasoning

src/datastruct/split_tree.zig

@@ -1,5 +1,5 @@
 const std = @import("std");
-const assert = std.debug.assert;
+const assert = @import("../quirks.zig").inlineAssert;
 const build_config = @import("../build_config.zig");
 const ArenaAllocator = std.heap.ArenaAllocator;
 const Allocator = std.mem.Allocator;