Add various tests for DFA testing

compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/45.kt

@@ -0,0 +1,30 @@
+// !LANGUAGE: +NewInference
+// !DIAGNOSTICS: -UNUSED_EXPRESSION -ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_VALUE -VARIABLE_WITH_REDUNDANT_INITIALIZER
+// SKIP_TXT
+
+/*
+ * KOTLIN DIAGNOSTICS NOT LINKED SPEC TEST (NEGATIVE)
+ *
+ * SECTIONS: dfa
+ * NUMBER: 45
+ * DESCRIPTION: Raw data flow analysis test
+ * HELPERS: classes, objects, typealiases, functions, enumClasses, interfaces, sealedClasses
+ */
+
+/*
+ * TESTCASE NUMBER: 1
+ * ISSUES: KT-22996
+ */
+fun case_1(x: Number?): Long? {
+    if (x is Long?) return <!DEBUG_INFO_SMARTCAST!>x<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number?")!>x<!>
+    return <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number?")!>x<!><!UNSAFE_CALL!>.<!>toLong()
+}
+
+/*
+ * TESTCASE NUMBER: 2
+ * ISSUES: KT-22997
+ */
+fun case_2(x: Number?): Long? {
+    if (x == null || x is Long) return <!TYPE_MISMATCH!>x<!> else return 0L
+}