Remove registry clear calls.

These registry clear calls were useful when TestTask and ModelTask could
be executed multiple times interactively. However, that is not possible
now so they are a liability that causes `bake all` to act
inconsistently.

Refs #3997

src/Console/Command/Task/ModelTask.php

@@ -631,7 +631,6 @@ class ModelTask extends BakeTask {
 		$filename = $path . 'Table' . DS . $name . 'Table.php';
 		$this->out("\n" . __d('cake_console', 'Baking table class for %s...', $name), 1, Shell::QUIET);
 		$this->createFile($filename, $out);
-		TableRegistry::clear();
 		return $out;
 	}
 

src/Console/Command/Task/TestTask.php

@@ -236,7 +236,6 @@ class TestTask extends BakeTask {
  * @return object And instance of the class that is going to be tested.
  */
 	public function buildTestSubject($type, $class) {
-		TableRegistry::clear();
 		if (strtolower($type) === 'table') {
 			list($namespace, $name) = namespaceSplit($class);
 			$name = str_replace('Table', '', $name);

tests/TestCase/Console/Command/Task/TestTaskTest.php

@@ -233,18 +233,6 @@ class TestTaskTest extends TestCase {
 	}
 
 /**
- * creating test subjects should clear the registry so the registry is always fresh
- *
- * @return void
- */
-	public function testRegistryClearWhenBuildingTestObjects() {
-		$articles = TableRegistry::get('Articles');
-		$this->Task->buildTestSubject('Table', 'Posts');
-
-		$this->assertFalse(TableRegistry::exists('Articles'));
-	}
-
-/**
  * Dataprovider for class name generation.
  *
  * @return array