JS: do not create variable for result, if inline function has one top level return

js/js.translator/testData/inlineSizeReduction/cases/oneTopLevelReturn.kt

@@ -0,0 +1,39 @@
+package foo
+
+// CHECK_CONTAINS_NO_CALLS: test1
+// CHECK_CONTAINS_NO_CALLS: test2
+// CHECK_VARS_COUNT: function=test1 count=0
+// CHECK_VARS_COUNT: function=test2 count=1
+
+var log = ""
+
+inline fun run1(fn: ()->Int): Int {
+    log += "1;"
+    return 1 + fn()
+}
+
+inline fun run2(fn: ()->Int): Int {
+    log += "2;"
+    return 2 + run1(fn)
+}
+
+inline fun run3(fn: ()->Int): Int {
+    log += "3;"
+    return 3 + run2(fn)
+}
+
+fun test1(x: Int): Int = run3 { x }
+
+fun test2(x: Int): Int {
+    val result = 1 + run3 { x }
+    return result
+}
+
+fun box(): String {
+    assertEquals(7, test1(1))
+    assertEquals("3;2;1;", log)
+
+    assertEquals(8, test2(1))
+
+    return "OK"
+}