Support Android in Connection Spec Tests (#6435)

okhttp-testing-support/src/main/kotlin/okhttp3/testing/PlatformRule.kt

@@ -15,6 +15,7 @@
  */
 package okhttp3.testing
 
+import android.os.Build
 import com.amazon.corretto.crypto.provider.AmazonCorrettoCryptoProvider
 import com.amazon.corretto.crypto.provider.SelfTestStatus
 import okhttp3.TestUtil
@@ -304,6 +305,17 @@ open class PlatformRule @JvmOverloads constructor(
     assumeTrue(PlatformVersion.majorVersion == majorVersion)
   }
 
+  fun androidSdkVersion(): Int? {
+    return if (Platform.isAndroid) {
+      Build.VERSION.SDK_INT
+    } else {
+      null
+    }
+  }
+
+  val isAndroid: Boolean
+    get() = Platform.Companion.isAndroid
+
   companion object {
     const val PROPERTY_NAME = "okhttp.platform"
     const val CONSCRYPT_PROPERTY = "conscrypt"