Resolve qualified nested class expressions

lookupNamespaceType now returns NamespaceType of a scope not only of the
namespace found by name, but also of the classifier static classes scope found
by the same name. This allows correct resolution of expressions
"Class.Nested.member()", where Class comes from Java (previously it was
resolved into a NamespaceDescriptor with a NamespaceType).

NamespaceDescriptor.getNamespaceType() is deleted since there are no sense in
namespace's NamespaceType alone anymore.

Also some minor refactoring (referencedName param is useless)

 #KT-1174 In Progress

compiler/testData/renderer/KeywordsInNames.kt

@@ -5,10 +5,10 @@ val `val` = 5
 `true` trait `trait`
 
 class `class`<`in`>(p: `in`?) {
-   class `class`
+   inner class `class`
 }
 
-val `is` = `class`.`class`()
+val `is` = `class`<`trait`>(null).`class`()
 val `in` = `class`<`trait`>(null)
 
 fun <`in`: `trait`> `trait`.`fun`(`false`: `trait`): `trait` where `in`: Number
@@ -21,7 +21,7 @@ fun <`in`: `trait`> `trait`.`fun`(`false`: `trait`): `trait` where `in`: Number
 //public constructor `class`<`in`>(p : `in`?) defined in `class`
 //<`in`> defined in `class`
 //value-parameter val p : `in`? defined in `class`.<init>
-//internal final class `class` defined in `class`
+//internal final inner class `class` defined in `class`
 //public constructor `class`() defined in `class`.`class`
 //internal val `is` : `class`.`class` defined in root package
 //internal val `in` : `class`<`trait`> defined in root package