[NI] Introduce flag to change constraint system for overload resolution

This commit doesn't change behaviour of any inference algorithm, it
 introduces opportunity to switch constraint system that is used for
 overload resolution and fix problematic cases by changing one enum
 entry.

 Due to fundamental changes, there are cases where a new inference
 algorithm reports overload resolution ambiguity errors (#KT-31670,
 #KT-31758), which is correct from its point of view. However, this is
 a breaking change and to really make it, we should be very confident
 and have enough motivation for it, therefore, we don't change behavior
 now in order to collect more examples (if there are any). And if we
 find a lot of erroneous examples, we'll be able to change the behavior
 quite simply

compiler/frontend/src/org/jetbrains/kotlin/config/AnalysisFlags.kt

@@ -29,4 +29,7 @@ object AnalysisFlags {
 
     @JvmStatic
     val allowResultReturnType by AnalysisFlag.Delegates.Boolean
+
+    @JvmStatic
+    val constraintSystemForOverloadResolution by AnalysisFlag.Delegates.ConstraintSystemForOverloadResolution
 }

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tower/KotlinResolutionStatelessCallbacksImpl.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.resolve.calls.tower
 
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.config.AnalysisFlags
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
@@ -28,6 +29,7 @@ import org.jetbrains.kotlin.resolve.calls.callResolverUtil.isInfixCall
 import org.jetbrains.kotlin.resolve.calls.callResolverUtil.isSuperOrDelegatingConstructorCall
 import org.jetbrains.kotlin.resolve.calls.components.KotlinResolutionCallbacks
 import org.jetbrains.kotlin.resolve.calls.components.KotlinResolutionStatelessCallbacks
+import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemBuilderImpl
 import org.jetbrains.kotlin.resolve.calls.inference.components.ConstraintInjector
 import org.jetbrains.kotlin.resolve.calls.inference.components.SimpleConstraintSystemImpl
 import org.jetbrains.kotlin.resolve.calls.inference.isCoroutineCallWithAdditionalInference
@@ -88,6 +90,9 @@ class KotlinResolutionStatelessCallbacksImpl(
     override fun createConstraintSystemForOverloadResolution(
         constraintInjector: ConstraintInjector, builtIns: KotlinBuiltIns
     ): SimpleConstraintSystem {
-        return SimpleConstraintSystemImpl(constraintInjector, builtIns)
+        return if (languageVersionSettings.getFlag(AnalysisFlags.constraintSystemForOverloadResolution).forNewInference())
+            SimpleConstraintSystemImpl(constraintInjector, builtIns)
+        else
+            ConstraintSystemBuilderImpl.forSpecificity()
     }
 }