KT-57468 Kotlin assignment plugin: operation name cannot be found

The problem results in broken import quick fix and import optimizer on
the IDE side [1].

`AssignResolutionAltererExtension` introduced a possibility to override
 resolution of assignment statements. The inconsistency though is
 that `KtSimpleNameReference.getResolvesByNames` doesn't return a name
 for the overridden `=`. Kotlin as a language doesn't support this [2].

This commit eliminates the drawback above:
1. It fixes the name `assign` the `=` can be resolved to [3].
   This eliminates the need to search for the name, bypassing the
   plugins.
2. `KtSimpleNameReference.getResolvesByNames` returns `assign` among
   other names in case it deals with binary `=` and assignment is
   resolved.
3. `KtCompilerPluginsProvider` was extended to check plugins' presence.
   K1 implementation added.

----------------------------------------------------------------
[1]: https://youtrack.jetbrains.com/issue/KTIJ-24390
[2]: OperatorConventions.getNameForOperationSymbol
     https://kotlinlang.org/docs/operator-overloading.html#augmented-assignments
[3]: OperatorConventions#ASSIGN_METHOD + AssignmentPluginNames

analysis/project-structure/src/org/jetbrains/kotlin/analysis/project/structure/KtCompilerPluginsProvider.kt

@@ -11,10 +11,20 @@ import org.jetbrains.kotlin.extensions.ProjectExtensionDescriptor
  * A service which can return extensions which are registered for some module
  */
 public abstract class KtCompilerPluginsProvider {
+
+    enum class CompilerPluginType {
+        ASSIGNMENT
+    }
+
     /**
      * Returns a list of extensions of a base [extensionType] which are registered for [module]
      *
      * These extensions are used in addition to those provided by the extension descriptor's [ProjectExtensionDescriptor.getInstances].
      */
     public abstract fun <T : Any> getRegisteredExtensions(module: KtSourceModule, extensionType: ProjectExtensionDescriptor<T>): List<T>
-}
+
+    /**
+     * Returns `true` if at least one plugin with requested `pluginType` is registered, `false` otherwise
+     */
+    public abstract fun isPluginOfTypeRegistered(module: KtSourceModule, pluginType: CompilerPluginType): Boolean
+}