Wasmtime: set the cranelift_wasm::Heap's min size (#5522)

This unlocks certain bounds checking optimizations in some
configurations. Wasn't able to measure any delta in sightglass, but still worth
doing anyways.

crates/cranelift/src/func_environ.rs

@@ -1471,7 +1471,7 @@ impl<'module_environment> cranelift_wasm::FuncEnvironment for FuncEnvironment<'m
         });
         Ok(self.heaps.push(HeapData {
             base: heap_base,
-            min_size: 0,
+            min_size: self.module.memory_plans[index].memory.minimum * u64::from(WASM_PAGE_SIZE),
             offset_guard_size,
             style: heap_style,
             index_type: self.memory_index_type(index),