Extract ConeClassifierLookupTag (aka SearchSymbol)

So, for classifiers there are both Symbols and LookupTags
The difference between them is that the former are assumed to have
a reference to the actual FirDeclaration while LookupTags
effectively contain only classId and
something informative may only be obtained by FirSession

#KT-24075 Fixed

idea/testData/fir/multiModule/mppSuperTypes/jvm/jvm.kt

@@ -13,7 +13,6 @@ actual open class A : X(), Y {
 class C : B() {
     fun test() {
         foo()
-        // This and next cannot be resolved yet due to lack of search symbols / projections
         bar()
         baz()
     }

idea/testData/fir/multiModule/mppSuperTypes/jvm/jvm.txt

@@ -23,8 +23,8 @@ FILE: jvm.kt
 
         public final function test(): R|kotlin/Unit| {
             R|/A.foo|()
-            <Unresolved name: bar>#()
-            <Unresolved name: baz>#()
+            R|/X.bar|()
+            R|/Y.baz|()
         }
 
     }