KT-2991 Don't generate UNNECESSARY_NOT_NULL_ASSERTION on variables of

generic type T:Any?

 #KT-2991 Fixed

compiler/testData/diagnostics/tests/nullableTypes/nullAssertOnTypeWithNullableUpperBound.kt

@@ -0,0 +1,14 @@
+fun <T> test(t: T): T {
+    if (t != null) {
+        return t<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
+    }
+    return t!!
+}
+
+fun <T> T.testThis(): String {
+    if (this != null) {
+        return this<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.toString()
+    }
+    return this!!.toString()
+}
+