Fix memory leaks in C API examples

lib/c-api/examples/exports-global.c

@@ -103,12 +103,15 @@ int main(int argc, const char* argv[]) {
         wasmer_last_error_message(error_message, error_length);
 
         printf("Attempted to set an immutable global: `%s`\n", error_message);
+        free(error_message);
     }
 
     wasm_val_t some_set_value = WASM_F32_VAL(21);
     wasm_global_set(some, &some_set_value);
     printf("`some` value: %.1f\n", some_value.of.f32);
 
+    wasm_globaltype_delete(one_type);
+    wasm_globaltype_delete(some_type);
     wasm_module_delete(module);
     wasm_extern_vec_delete(&exports);
     wasm_instance_delete(instance);

lib/c-api/examples/imports-exports.c

@@ -63,6 +63,7 @@ int main(int argc, const char* argv[]) {
 
     printf("Instantiating module...\n");
     wasm_instance_t* instance = wasm_instance_new(store, module, &import_object, NULL);
+    wasm_extern_vec_delete(&import_object);
 
     if (!instance) {
       printf("> Error instantiating module!\n");

lib/c-api/examples/instance.c

@@ -15,6 +15,7 @@ int main(int argc, const char* argv[]) {
     wasm_byte_vec_new(&wat, strlen(wat_string), wat_string);
     wasm_byte_vec_t wasm_bytes;
     wat2wasm(&wat, &wasm_bytes);
+    wasm_byte_vec_delete(&wat);
 
     printf("Creating the store...\n");
     wasm_engine_t* engine = wasm_engine_new();

lib/c-api/examples/wasi.c

@@ -69,13 +69,7 @@ int main(int argc, const char* argv[]) {
 
   // Instantiate.
   printf("Instantiating module...\n");
-  wasm_importtype_vec_t import_types;
-  wasm_module_imports(module, &import_types);
-
   wasm_extern_vec_t imports;
-  wasm_extern_vec_new_uninitialized(&imports, import_types.size);
-  wasm_importtype_vec_delete(&import_types);
-
   bool get_imports_result = wasi_get_imports(store, module, wasi_env, &imports);
 
   if (!get_imports_result) {
@@ -153,6 +147,7 @@ int main(int argc, const char* argv[]) {
     fclose(memory_stream);
 
     printf("WASI Stdout: `%.*s`\n", (int) stdout_size, stdout);
+    free(stdout);
   }