[FIR] Don't create redundant substitution scopes

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/substitution/Substitutors.kt

@@ -120,7 +120,11 @@ abstract class AbstractConeSubstitutor : ConeSubstitutor() {
 }
 
 fun substitutorByMap(substitution: Map<FirTypeParameterSymbol, ConeKotlinType>): ConeSubstitutor {
-    if (substitution.isEmpty()) return ConeSubstitutor.Empty
+    // If all arguments match parameters, then substitutor isn't needed
+    if (substitution.all { (parameterSymbol, argumentType) ->
+            (argumentType as? ConeTypeParameterType)?.lookupTag?.typeParameterSymbol == parameterSymbol
+        }
+    ) return ConeSubstitutor.Empty
     return ConeSubstitutorByMap(substitution)
 }
 

compiler/fir/resolve/testData/resolve/expresssions/genericUsedInFunction.txt

@@ -8,7 +8,7 @@ FILE: genericUsedInFunction.kt
             public get(): R|T|
 
         public final fun foo(): R|T| {
-            ^foo this@R|/Generic|.R|FakeOverride</Generic.value: R|T|>|
+            ^foo this@R|/Generic|.R|/Generic.value|
         }
 
     }

compiler/fir/resolve/testData/resolve/expresssions/protectedVisibility.txt

@@ -91,7 +91,7 @@ FILE: protectedVisibility.kt
             public get(): R|T|
 
         protected open fun foo(): R|T| {
-            ^foo this@R|/Generic|.R|FakeOverride</Generic.x: R|T|>|
+            ^foo this@R|/Generic|.R|/Generic.x|
         }
 
     }

compiler/fir/resolve/testData/resolve/genericConstructors.txt

@@ -13,7 +13,7 @@ FILE: genericConstructors.kt
             super<R|kotlin/Any|>()
         }
 
-        public final val myE: R|E| = this@R|/B|.R|FakeOverride</B.id: R|E|>|(R|<local>/e|)
+        public final val myE: R|E| = this@R|/B|.R|/B.id|(R|<local>/e|)
             public get(): R|E|
 
         public final val a: R|A<E>| = R|/A.A|<R|E|>(R|<local>/e|)

compiler/fir/resolve/testData/resolve/problems2.txt

@@ -9,7 +9,7 @@ FILE: problems2.kt
         }
 
         public final fun intern(obj: R|T|): R|kotlin/Int?| {
-            ^intern this@R|/Interner|.R|FakeOverride</Interner.find: R|kotlin/Int?|>|(R|<local>/obj|)
+            ^intern this@R|/Interner|.R|/Interner.find|(R|<local>/obj|)
         }
 
     }

compiler/fir/resolve/testData/resolveWithStdlib/hashTableWithForEach.txt

@@ -14,7 +14,7 @@ FILE: hashTableWithForEach.kt
                 when () {
                     R|/DEBUG| ->  {
                         ^ Q|java/util/Collections|.R|java/util/Collections.unmodifiableSet|<R|ft<kotlin/collections/MutableMap.MutableEntry<K, V>, kotlin/collections/MutableMap.MutableEntry<K, V>?>!|>(R|kotlin/collections/mutableSetOf|<R|kotlin/collections/MutableMap.MutableEntry<K, V>|>().R|kotlin/apply|<R|kotlin/collections/MutableSet<kotlin/collections/MutableMap.MutableEntry<K, V>>|>(<L> = apply@fun R|kotlin/collections/MutableSet<kotlin/collections/MutableMap.MutableEntry<K, V>>|.<anonymous>(): R|kotlin/Unit| <kind=EXACTLY_ONCE>  {
-                            this@R|/SomeHashTable|.R|FakeOverride</SomeHashTable.forEach: R|kotlin/Unit|>|(<L> = forEach@fun <anonymous>(key: R|K|, value: R|V|): R|kotlin/Unit| {
+                            this@R|/SomeHashTable|.R|/SomeHashTable.forEach|(<L> = forEach@fun <anonymous>(key: R|K|, value: R|V|): R|kotlin/Unit| {
                                 ^ this@R|special/anonymous|.R|FakeOverride<kotlin/collections/MutableSet.add: R|kotlin/Boolean|>|(R|/SomeHashTable.Entry.Entry|<R|K|, R|V|>(R|<local>/key|, R|<local>/value|))
                             }
                             )

compiler/fir/resolve/testData/resolveWithStdlib/j+k/StaticGenericMethod.txt

@@ -6,14 +6,14 @@ FILE: User.kt
             super<R|kotlin/Any|>()
         }
 
-        private final var settings: R|T| = this@R|/User|.R|FakeOverride</User.createSettings: R|T|>|()
+        private final var settings: R|T| = this@R|/User|.R|/User.createSettings|()
             private get(): R|T|
             private set(value: R|T|): R|kotlin/Unit|
 
         protected abstract fun createSettings(): R|T|
 
         public final fun foo(): R|kotlin/Unit| {
-            this@R|/User|.R|FakeOverride</User.settings: R|T|>| = Q|StaticOwner|.R|/StaticOwner.newInstance|<R|ft<T, T?>!|>(this@R|/User|.R|FakeOverride</User.settings: R|T|>|.R|kotlin/jvm/javaClass|)
+            this@R|/User|.R|/User.settings| = Q|StaticOwner|.R|/StaticOwner.newInstance|<R|ft<T, T?>!|>(this@R|/User|.R|/User.settings|.R|kotlin/jvm/javaClass|)
         }
 
     }

compiler/testData/codegen/box/arrays/kt238.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun t1 () {
     val a1 = arrayOfNulls<String>(1)
     a1[0] = "0" //ok

compiler/testData/codegen/box/classes/privateToThis.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 class A<in I>(init_o: I, private val init_k: I) {
     private val o: I = init_o
     private fun k(): I = init_k