Catch panics on the FFI boundary between the runtime and the host for wasmtime (#11189)

* Catch panics on the FFI boundary between the runtime and the host for `wasmtime`

* Use an already existing test runtime function

* Merge the tests together

substrate/client/executor/runtime-test/src/lib.rs

@@ -113,7 +113,9 @@ sp_core::wasm_export_functions! {
 	   }
    }
 
-   fn test_exhaust_heap() -> Vec<u8> { Vec::with_capacity(16777216) }
+	fn test_allocate_vec(size: u32) -> Vec<u8> {
+		Vec::with_capacity(size as usize)
+	}
 
    fn test_fp_f32add(a: [u8; 4], b: [u8; 4]) -> [u8; 4] {
 	   let a = f32::from_le_bytes(a);