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

compiler/frontend/src/org/jetbrains/kotlin/resolve/extensions/AssignResolutionAltererExtension.kt

@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.types.expressions.ExpressionTypingComponents
 import org.jetbrains.kotlin.types.expressions.ExpressionTypingContext
 import org.jetbrains.kotlin.types.expressions.KotlinTypeInfo
 
+
 @InternalNonStableExtensionPoints
 interface AssignResolutionAltererExtension : AnnotationBasedExtension {
     companion object : ProjectExtensionDescriptor<AssignResolutionAltererExtension>(