Remove alloc error handler (#417)

* Increases minimum nightly version

- [x] No changelog update needed

agb/src/agb_alloc/mod.rs

@@ -120,15 +120,6 @@ pub(crate) unsafe fn number_of_blocks() -> u32 {
     GLOBAL_ALLOC.number_of_blocks()
 }
 
-#[alloc_error_handler]
-fn alloc_error(layout: Layout) -> ! {
-    panic!(
-        "Failed to allocate size {} with alignment {}",
-        layout.size(),
-        layout.align()
-    );
-}
-
 fn iwram_data_end() -> usize {
     extern "C" {
         static __iwram_end: usize;

agb/src/lib.rs

@@ -10,7 +10,6 @@
     any(test, feature = "testing"),
     reexport_test_harness_main = "test_main"
 )]
-#![feature(alloc_error_handler)]
 #![feature(allocator_api)]
 #![feature(asm_const)]
 #![warn(clippy::all)]