FIR: Do not add alias for variables with explicit type

compiler/testData/diagnostics/tests/smartCasts/toInvisible.kt

@@ -0,0 +1,45 @@
+// SKIP_TXT
+// FILE: a/A.java
+package a;
+public interface A {
+    B b();
+}
+
+// FILE: a/B.java
+package a;
+public interface B {
+    void bar();
+}
+
+// FILE: a/AImpl.java
+package a;
+
+public class AImpl implements A {
+    @Override
+    public BImpl b() {
+        return new BImpl();
+    }
+}
+
+class BImpl implements B {
+    @Override
+    public void bar() {}
+}
+
+// FILE: main.kt
+import a.A
+import a.AImpl
+
+fun test1(a: A) {
+    if (a is AImpl) {
+        (a as A).b().bar() // OK
+        <!INACCESSIBLE_TYPE!><!DEBUG_INFO_SMARTCAST!>a<!>.b()<!>.<!INVISIBLE_MEMBER!>bar<!>()
+    }
+}
+
+fun test2(aImpl: AImpl) {
+    val a: A = aImpl
+    (a <!USELESS_CAST!>as A<!>).b().bar() // OK
+    a.b().bar() // Works at FE1.0, fails at FIR
+}
+