FIR: Reimplement conflicts checker to detect conflicts in different files

also pass correct ScopeSession to checkers
fixes some IC tests

compiler/tests-spec/testData/diagnostics/linked/overload-resolution/building-the-overload-candidate-set-ocs/call-without-an-explicit-receiver/p-5/neg/2.4.fir.kt

@@ -8,7 +8,7 @@ package testsCase1
 import libPackageCase1.*
 import libPackageCase1Explicit.emptyArray
 
-fun <T> Case1.emptyArray(): Array<T> = TODO()
+<!CONFLICTING_OVERLOADS!>fun <T> Case1.emptyArray(): Array<T><!> = TODO()
 
 class Case1(){
 
@@ -33,7 +33,7 @@ public fun <T> emptyArray(): Array<T> = TODO()
 // FILE: LibtestsPack1.kt
 // TESTCASE NUMBER: 1
 package testsCase1
-fun <T> Case1.emptyArray(): Array<T> = TODO()
+<!CONFLICTING_OVERLOADS!>fun <T> Case1.emptyArray(): Array<T><!> = TODO()
 
 public fun <T> emptyArray(): Array<T> = TODO()
 
@@ -46,7 +46,7 @@ package testsCase2
 import libPackageCase2.*
 import libPackageCase2Explicit.emptyArray
 
-fun <T> Case2.emptyArray(): Array<T> = TODO()
+<!CONFLICTING_OVERLOADS!>fun <T> Case2.emptyArray(): Array<T><!> = TODO()
 
 class Case2(){
 
@@ -77,6 +77,6 @@ public fun <T> emptyArray(): Array<T> = TODO()
 // FILE: LibtestsPack2.kt
 // TESTCASE NUMBER: 2
 package testsCase2
-fun <T> Case2.emptyArray(): Array<T> = TODO()
+<!CONFLICTING_OVERLOADS!>fun <T> Case2.emptyArray(): Array<T><!> = TODO()
 
 public fun <T> emptyArray(): Array<T> = TODO()

compiler/tests-spec/testData/diagnostics/notLinked/annotations/type-annotations/neg/3.fir.kt

@@ -5,8 +5,6 @@
 annotation class Ann(val x: Int)
 
 // TESTCASE NUMBER: 1
-class Inv<T>
-
 fun foo(i: Inv<@Ann(unresolved_reference) String>) {}
 
 // TESTCASE NUMBER: 2

compiler/tests-spec/testData/diagnostics/notLinked/annotations/type-annotations/neg/4.fir.kt

@@ -2,6 +2,4 @@
 @Target(AnnotationTarget.TYPE)
 annotation class Ann(val x: Int)
 
-class Inv<T>
-
 fun case_1(): Inv<@Ann(unresolved_reference) String> = TODO()

compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/1.fir.kt

@@ -183,8 +183,8 @@ fun case_13(x: <!UNRESOLVED_REFERENCE!>otherpackage.Case13?<!>) =
     <!DEBUG_INFO_EXPRESSION_TYPE("ERROR CLASS: Can't resolve when expression")!>if ((x == null !is Boolean) !== true) {
         throw Exception()
     } else {
-        <!DEBUG_INFO_EXPRESSION_TYPE("ERROR CLASS: Symbol not found, for `otherpackage.Case13?`")!>x<!>
-        <!DEBUG_INFO_EXPRESSION_TYPE("ERROR CLASS: Symbol not found, for `otherpackage.Case13?`")!>x<!>.<!AMBIGUITY!>equals<!>(x)
+        <!DEBUG_INFO_EXPRESSION_TYPE("ERROR CLASS: Symbol not found for otherpackage.Case13?")!>x<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("ERROR CLASS: Symbol not found for otherpackage.Case13?")!>x<!>.<!AMBIGUITY!>equals<!>(x)
     }<!>
 
 // TESTCASE NUMBER: 14