Migrate testdata to new lambda syntax

js/js.translator/testData/jsCode/cases/function.kt

@@ -5,7 +5,7 @@ fun callWithArgs(sumFunc: (Int, Int) -> Int, a: Int, b: Int): Int {
 }
 
 fun box(): String {
-    val kotlinSum: (Int, Int) -> Int = {(a, b) -> a + b}
+    val kotlinSum: (Int, Int) -> Int = { a, b -> a + b}
     val jsSum: (Int, Int) -> Int = js("function (a, b) { return a + b; }")
     assertEquals(callWithArgs(kotlinSum, 1, 2), callWithArgs(jsSum, 1, 2))
 

js/js.translator/testData/jsCode/cases/invocation.kt

@@ -3,7 +3,7 @@ package foo
 fun run<A, B, C>(a: A, b: B, func: (A, B) -> C): C = js("func(a, b)")
 
 fun box(): String {
-    assertEquals(3, run(1, 2) {(a, b) -> a + b})
+    assertEquals(3, run(1, 2) { a, b -> a + b})
 
     return "OK"
 }