Preliminary declaration visitor for estimating local variable's predictability for smart casts

Predictability estimation algorithm is completely new, but backward compatibility should present.
A large set of tests. Some updated tests.
Smart casts allowed for captured variables if they are not modified in closure #KT-9051 Fixed
Also #KT-8643 Fixed
Also #KT-7976 Fixed
Correct handling of lambda arguments in functions #KT-9143 Fixed

compiler/testData/diagnostics/tests/smartCasts/variables/accessorAndFunction.kt

@@ -0,0 +1,23 @@
+class My {
+
+    val y: Int 
+        get() {
+            var x: Int?
+            x = 3
+            return <!DEBUG_INFO_SMARTCAST!>x<!>.hashCode()
+        }
+
+    fun test() {
+        var x: Int?
+        x = 2
+        <!DEBUG_INFO_SMARTCAST!>x<!>.hashCode()
+        fun bb() {
+           var <!NAME_SHADOWING!>x<!>: Any?
+           x = 4
+           <!SMARTCAST_IMPOSSIBLE!>x<!>.hashCode()
+        }
+        x = 4
+        // Really smart cast is possible but name shadowing by bb() prevents it
+        <!SMARTCAST_IMPOSSIBLE!>x<!>.hashCode()
+    }
+}

compiler/testData/diagnostics/tests/smartCasts/variables/accessorAndFunction.txt

@@ -0,0 +1,10 @@
+package
+
+public final class My {
+    public constructor My()
+    public final val y: kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final fun test(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/smartCasts/variables/inPropertySam.kt

@@ -0,0 +1,18 @@
+// FILE: My.java
+
+public interface My {
+    String foo(String arg);
+}
+
+// FILE: test.kt
+
+class Your {
+    val x = My() {
+        arg: String? ->
+        var y = arg
+        val z: String
+        if (y != null) z = <!DEBUG_INFO_SMARTCAST!>y<!>
+        else z = "42"
+        z
+    }
+}

compiler/testData/diagnostics/tests/smartCasts/variables/inPropertySam.txt

@@ -0,0 +1,18 @@
+package
+
+public /*synthesized*/ fun My(/*0*/ function: (kotlin.String!) -> kotlin.String!): My
+
+public interface My {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(/*0*/ arg: kotlin.String!): kotlin.String!
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class Your {
+    public constructor Your()
+    public final val x: My
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/smartCasts/variables/lambdaBetweenArguments.kt

@@ -0,0 +1,9 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+fun foo(x: Int, f: () -> Unit, y: Int) {}
+
+fun bar() {
+    var x: Int?
+    x = 4
+    foo(<!DEBUG_INFO_SMARTCAST!>x<!>, { x = null; x<!UNSAFE_CALL!>.<!>hashCode() }, <!SMARTCAST_IMPOSSIBLE!>x<!>)
+}

compiler/testData/diagnostics/tests/smartCasts/variables/lambdaBetweenArguments.txt

@@ -0,0 +1,4 @@
+package
+
+public fun bar(): kotlin.Unit
+public fun foo(/*0*/ x: kotlin.Int, /*1*/ f: () -> kotlin.Unit, /*2*/ y: kotlin.Int): kotlin.Unit