KT-10005 Java to Kotlin: do not convert type cast to cast to nullable if it should not be null

#KT-10005 Fixed

j2k/testData/fileOrElement/typeCastExpression/beforeDot.java

@@ -0,0 +1,6 @@
+public class A {
+    void foo(Object o) {
+        if (o == null) return;
+        int length = ((String) o).length();
+    }
+}

j2k/testData/fileOrElement/typeCastExpression/beforeDot.kt

@@ -0,0 +1,6 @@
+class A {
+    internal fun foo(o: Any?) {
+        if (o == null) return
+        val length = (o as String).length
+    }
+}