Support new form of definitely non-nullable types: T & Any

^KT-26245 In Progress

compiler/testData/diagnostics/tests/explicitDefinitelyNotNullableViaIntersection/isAsOperators.kt

@@ -0,0 +1,17 @@
+// FIR_IDENTICAL
+// SKIP_TXT
+// !LANGUAGE: -DefinitelyNotNullTypeParameters
+
+fun Any.bar() {}
+fun Boolean.baz() {}
+
+var x: Int = 0
+
+inline fun <reified T> foo(v: Any?): T {
+    if (x > 0) 1 else v as T <!SYNTAX!>& Any<!>
+    if (x > 1) 2 else v as? T <!SYNTAX!>& Any<!>
+    if (x > 2) 3 else v is T <!SYNTAX!>& Any<!>
+    if (x > 3) 4 else v !is T <!SYNTAX!>& Any<!>
+
+    return v as T <!SYNTAX!>& Any<!>
+}