Improve configuration and tests for native-image (#509)

* Don't expose JDK internal classes; instead solve msgpack issue with `--initialize-at-run-time`.
* Use quick build mode for non-release builds:  40% faster compilation, 20% smaller executable.
* Remove options that were commented out.
* Also run ServerTest against native executable

pkl-server/pkl-server.gradle.kts

@@ -2,6 +2,7 @@ plugins {
   pklAllProjects
   pklJavaLibrary
   pklKotlinLibrary
+  pklNativeBuild
 }
 
 dependencies {
@@ -14,6 +15,24 @@ dependencies {
 }
 
 tasks.test {
-  inputs.dir("src/test/files/SnippetTests/input").withPropertyName("snippetTestsInput").withPathSensitivity(PathSensitivity.RELATIVE)
-  inputs.dir("src/test/files/SnippetTests/output").withPropertyName("snippetTestsOutput").withPathSensitivity(PathSensitivity.RELATIVE)
+  inputs.dir("src/test/files/SnippetTests/input")
+    .withPropertyName("snippetTestsInput")
+    .withPathSensitivity(PathSensitivity.RELATIVE)
+  inputs.dir("src/test/files/SnippetTests/output")
+    .withPropertyName("snippetTestsOutput")
+    .withPathSensitivity(PathSensitivity.RELATIVE)
+  exclude("**/NativeServerTest.*")
 }
+
+val nativeTest by tasks.registering(Test::class) {
+  dependsOn(":pkl-cli:assembleNative")
+  testClassesDirs = files(tasks.test.get().testClassesDirs)
+  classpath = tasks.test.get().classpath
+  include("**/NativeServerTest.*")
+}
+
+val testNative by tasks.existing
+testNative {
+  dependsOn(nativeTest)
+}
+