Wire -Pjmh.includes and -PtestJvm into internal-api JMH config (#11703)

Wire -Pjmh.includes and -PtestJvm into internal-api JMH config

Without this, -Pjmh.includes is silently ignored by the me.champeau.jmh
plugin, requiring a full fat-jar build to run a single benchmark.
-PtestJvm was also ignored for JMH execution, defaulting to the Gradle
daemon JVM regardless of the requested version.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Merge branch 'master' into dougqh/jmh-gradle-improvements

Co-authored-by: devflow.devflow-routing-intake <devflow.devflow-routing-intake@kubernetes.us1.ddbuild.io>

Author: dougqh

internal-api/build.gradle.kts

@@ -1,3 +1,4 @@
+import datadog.gradle.plugin.testJvmConstraints.TestJvmSpec
 import de.thetaphi.forbiddenapis.gradle.CheckForbiddenApis
 import groovy.lang.Closure
 
@@ -274,4 +275,13 @@ dependencies {
 jmh {
   jmhVersion = libs.versions.jmh.get()
   duplicateClassesStrategy = DuplicatesStrategy.EXCLUDE
+
+  if (project.hasProperty("jmh.includes")) {
+    includes.add(project.property("jmh.includes") as String)
+  }
+
+  if (project.hasProperty("testJvm")) {
+    val testJvmSpec = TestJvmSpec(project)
+    jvm.set(testJvmSpec.javaTestLauncher.map { it.executablePath.asFile.absolutePath })
+  }
 }