fix: kotlin compiler daemon memory settings (#8829)

Also, avoid warning by explicitly opting in coroutines.

Author: bric3

dd-java-agent/instrumentation/kotlin-coroutines/src/test/groovy/KotlinCoroutineInstrumentationTest.groovy

@@ -1,7 +1,10 @@
 import datadog.trace.core.DDSpan
 import datadog.trace.instrumentation.kotlin.coroutines.AbstractKotlinCoroutineInstrumentationTest
+import kotlin.OptIn
 import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 
+@OptIn(markerClass = ExperimentalCoroutinesApi)
 class KotlinCoroutineInstrumentationTest extends AbstractKotlinCoroutineInstrumentationTest<KotlinCoroutineTests> {
 
   @Override

dd-java-agent/instrumentation/kotlin-coroutines/src/test/kotlin/KotlinCoroutineTests.kt

@@ -3,11 +3,13 @@ import datadog.trace.bootstrap.instrumentation.api.AgentTracer.get
 import datadog.trace.instrumentation.kotlin.coroutines.CoreKotlinCoroutineTests
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings
 import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.channels.actor
 import kotlinx.coroutines.channels.consumeEach
 import kotlinx.coroutines.channels.produce
 import kotlinx.coroutines.channels.toChannel
 
+@OptIn(ExperimentalCoroutinesApi::class)
 @SuppressFBWarnings("NP_PARAMETER_MUST_BE_NONNULL_BUT_MARKED_AS_NULLABLE")
 class KotlinCoroutineTests(dispatcher: CoroutineDispatcher) : CoreKotlinCoroutineTests(dispatcher) {
 

gradle/java_no_deps.gradle

@@ -228,9 +228,7 @@ project.afterEvaluate {
   if (project.plugins.hasPlugin('kotlin')) {
     ['compileKotlin', 'compileTestKotlin'].each { type ->
       tasks.named(type).configure {
-        kotlinOptions {
-          freeCompilerArgs += '-Xmx256m'
-        }
+        kotlinDaemonJvmArguments = ["-Xmx256m", "-XX:+UseParallelGC"]
       }
     }
   }