Add test cases for conflicting use and definition in same ns (stas)

Author: igorw

Zend/tests/use_const/define_imported.phpt

@@ -0,0 +1,14 @@
+--TEST--
+defining const with same name as imported should fail
+--FILE--
+<?php
+
+namespace {
+    use const foo\bar;
+
+    const bar = 42;
+}
+
+?>
+--EXPECTF--
+Fatal error: Cannot declare const bar because the name is already in use in %s on line %d

Zend/tests/use_const/define_imported_before.phpt

@@ -0,0 +1,14 @@
+--TEST--
+using const with same name as defined should fail
+--FILE--
+<?php
+
+namespace {
+    const bar = 42;
+
+    use const foo\bar;
+}
+
+?>
+--EXPECTF--
+Fatal error: Cannot use const foo\bar as bar because the name is already in use in %s on line %d

Zend/tests/use_const/shadow_global_same_ns.phpt

@@ -0,0 +1,14 @@
+--TEST--
+defining function with same name as imported should fail
+--FILE--
+<?php
+
+namespace {
+    use function foo\bar;
+
+    function bar() {}
+}
+
+?>
+--EXPECTF--
+Fatal error: Cannot declare function bar because the name is already in use in %s on line %d

Zend/tests/use_function/define_imported.phpt

@@ -0,0 +1,14 @@
+--TEST--
+using function with same name as defined should fail
+--FILE--
+<?php
+
+namespace {
+    function bar() {}
+
+    use function foo\bar;
+}
+
+?>
+--EXPECTF--
+Fatal error: Cannot use function foo\bar as bar because the name is already in use in %s on line %d