[FIR] Do not include transitive friend dependencies in symbol provider

When flattening a dependency FirSymbolProvider, make sure transitive
dependency FirSymbolProviders are not included. This requires checking
that nested symbol provider sessions match the composite symbol provider
session when they are both source sessions.

^KT-60614 Fixed

compiler/testData/diagnostics/tests/multimodule/friendModule.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_VARIABLE
 // MODULE: m1
 // FILE: a.kt
@@ -35,3 +34,20 @@ fun test() {
     inst.B()
 }
 
+// MODULE: m3()(m2)
+// FILE: c.kt
+
+import <!UNRESOLVED_REFERENCE!>p<!>.*
+
+fun test3() {
+    val _a = <!UNRESOLVED_REFERENCE!>a<!>
+    val _v = <!UNRESOLVED_REFERENCE!>v<!>
+    <!UNRESOLVED_REFERENCE!>a<!>()
+    <!UNRESOLVED_REFERENCE!>B<!>()
+
+    val inst = <!UNRESOLVED_REFERENCE!>A<!>()
+    val ia = <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>inst<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>a<!>
+    val iv = <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>inst<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>v<!>
+    <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>inst<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>a<!>()
+    <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>inst<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>B<!>()
+}