Current package members to have less priority than explicit imports

compiler/testData/diagnostics/tests/imports/CurrentPackageAndExplicitImport.kt

@@ -0,0 +1,16 @@
+// FILE: a.kt
+package a
+
+open class Y
+
+// FILE: b.kt
+package b
+
+class X
+
+// FILE: b1.kt
+package b
+
+import a.Y as X
+
+class Y : X() // class from explicit import should take priority