Fixes setter paratemer default value (#8479)

* Fixes setter paratemer default value

* Not changes doesn't mutate loose variable

packages/babel-plugin-transform-parameters/test/fixtures/parameters/default-setter/exec.js

@@ -0,0 +1,9 @@
+const defaultValue = 1;
+const obj = {
+  set field(num = defaultValue) {
+    this.num = num;
+  }
+};
+obj.field = void 0;
+
+expect(obj.num).toBe(defaultValue);

packages/babel-plugin-transform-parameters/test/fixtures/parameters/default-setter/input.js

@@ -0,0 +1,5 @@
+const obj = {
+  set field(num = 1) {
+    this.num = num;
+  }
+};

packages/babel-plugin-transform-parameters/test/fixtures/parameters/default-setter/output.js

@@ -0,0 +1,10 @@
+var obj = {
+  set field(num) {
+    if (num === void 0) {
+      num = 1;
+    }
+
+    this.num = num;
+  }
+
+};