rename generation test names to be more descriptive

test/fixtures/generation/harmony-edgecase/default-parameter/expected.js

@@ -0,0 +1,10 @@
+function a(p = 20) {
+}
+function b(p, q = 30) {
+}
+function c(p, q = 30, ...r) {
+}
+(p = 20) => {
+};
+(p = 20, ...q) => {
+};