Created module idea-test-framework and moved classes needed for idea tests there

Moved tests for completion and their test data into module idea-completion

idea/idea-completion/testData/smart/WithPrefix.kt

@@ -0,0 +1,19 @@
+open class Foo
+class Bar : Foo()
+
+val xfoo = Foo()
+val xbar = Bar()
+val xo : Any = ""
+
+fun f(xp1 : Foo, xp2 : Bar, xp3 : String, p4 : Foo) {
+    var a : Foo
+    a = x<caret>
+}
+
+// EXIST: xfoo
+// EXIST: xbar
+// ABSENT: xo
+// EXIST: xp1
+// EXIST: xp2
+// ABSENT: xp3
+// ABSENT: p4