[Plugin] Fix search of the benchmark compilation of a multiplatform target

MPP plugin has added "Compilation" postfix to configuration names of compilations.
See KT-35916.

Author: Abduqodiri Qurbonzoda

plugin/main/src/kotlinx/benchmark/gradle/BenchmarksExtension.kt

@@ -4,6 +4,7 @@ import groovy.lang.*
 import org.gradle.api.*
 import org.gradle.api.plugins.*
 import org.jetbrains.kotlin.gradle.dsl.*
+import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
 import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
 import org.jetbrains.kotlin.gradle.plugin.mpp.*
 import org.jetbrains.kotlin.gradle.targets.js.ir.KotlinJsIrCompilation
@@ -49,9 +50,8 @@ open class BenchmarksExtension(val project: Project) {
 
             when {
                 multiplatform != null -> {
-                    val compilations = multiplatform.targets.flatMap { it.compilations }
-                    val compilation = compilations.singleOrNull { it.apiConfigurationName.removeSuffix("Api") == name }
-                    when (compilation) {
+                    val target = multiplatform.targets.findByName(name)
+                    when (val compilation = target?.compilations?.findByName(KotlinCompilation.MAIN_COMPILATION_NAME)) {
                         null -> {
                             project.logger.warn("Warning: Cannot find a benchmark compilation '$name', ignoring.")
                             BenchmarkTarget(this, name) // ignore
@@ -78,8 +78,7 @@ open class BenchmarksExtension(val project: Project) {
 
                 }
                 javaExtension != null -> {
-                    val sourceSet = javaExtension.sourceSets.findByName(name)
-                    when (sourceSet) {
+                    when (val sourceSet = javaExtension.sourceSets.findByName(name)) {
                         null -> {
                             project.logger.warn("Warning: Cannot find a benchmark sourceSet '$name', ignoring.")
                             BenchmarkTarget(this, name) // ignore