Bulk lazy initialization of FunctionDefinitions (#1425)

Signed-off-by: Takeshi Yoneda <t.y.mathetake@gmail.com>
Co-authored-by: Edoardo Vacchi <evacchi@users.noreply.github.com>

internal/wasm/module_test.go

@@ -376,8 +376,9 @@ func TestModule_validateStartSection(t *testing.T) {
 	t.Run("imported valid func", func(t *testing.T) {
 		index := Index(1)
 		m := Module{
-			StartSection: &index,
-			TypeSection:  []FunctionType{{}, {Results: []ValueType{ValueTypeI32}}},
+			StartSection:        &index,
+			TypeSection:         []FunctionType{{}, {Results: []ValueType{ValueTypeI32}}},
+			ImportFunctionCount: 2,
 			ImportSection: []Import{
 				{Type: ExternTypeFunc, DescFunc: 1},
 				// import with index 1 is global but this should be skipped when searching imported functions.