Support single-underscore named variables in JVM backend

There are mainly two kind of changes:
- skipping 'componentX' calls for destructuring entries named _
- fixing local variable table for them
 - skip entries for destructuring entries named _
 - use $noName_<i> format for lambda parameters named _

 #KT-3824 Fixed
 #KT-2783 Fixed

compiler/testData/codegen/box/multiDecl/UnderscoreNames.kt

@@ -0,0 +1,14 @@
+class A {
+    operator fun component1() = 1
+    operator fun component2() = 2
+}
+
+fun box() : String {
+    val (_, b) = A()
+
+    val (a, _) = A()
+
+    val (`_`, c) = A()
+
+    return if (a == 1 && b == 2 && _ == 1 && c == 2) "OK" else "fail"
+}

compiler/testData/codegen/box/multiDecl/forRange/UnderscoreNames.kt

@@ -0,0 +1,43 @@
+class Range(val from : C, val to: C) {
+    operator fun iterator() = It(from, to)
+}
+
+class It(val from: C, val to: C) {
+    var c = from.i
+
+    operator fun next(): C {
+        val next = C(c)
+        c++
+        return next
+    }
+
+    operator fun hasNext(): Boolean = c <= to.i
+}
+
+class C(val i : Int) {
+    operator fun component1() = i + 1
+    operator fun component2() = i + 2
+    operator fun rangeTo(c: C) = Range(this, c)
+}
+
+fun doTest(): String {
+    var s = ""
+    for ((a, _) in C(0)..C(2)) {
+        s += "$a;"
+    }
+
+    for ((_, b) in C(1)..C(3)) {
+        s += "$b;"
+    }
+
+    for ((_, `_`) in C(2)..C(4)) {
+        s += "$_;"
+    }
+
+    return s
+}
+
+fun box(): String {
+    val s = doTest()
+    return if (s == "1;2;3;3;4;5;4;5;6;") "OK" else "fail: $s"
+}

compiler/testData/codegen/box/multiDecl/forRange/UnderscoreNamesDontCallComponent.kt

@@ -0,0 +1,15 @@
+class A {
+    operator fun component1() = "O"
+    operator fun component2(): String = throw RuntimeException("fail 0")
+    operator fun component3() = "K"
+}
+
+fun box(): String {
+    val aA = Array(1) { A() }
+
+    for ((x, _, z) in aA) {
+        return x + z
+    }
+
+    return "OK"
+}