[Gradle] Rework runToolInSeparateProcess

* Make it using JVM arguments file (@-file) on JDK 9+ for avoiding issues with too long command line on Windows
* Remove testKotlinCompileInFolderWithSpaces
  We cover compiler execution against paths or classpath with spaces on the BTA layer. This test was introduced specifically for testing the utility function of running separate processes from KGP with command-line argument files ("@-files").
* Add a functional test for the utility function verification
^KT-80875 Fixed

Author: ALikhachev

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/KotlinGradlePluginIT.kt

@@ -85,17 +85,6 @@ class KotlinGradleIT : KGPBaseTest() {
         }
     }
 
-    @DisplayName("Project path contains spaces")
-    @GradleTest
-    fun testKotlinCompileInFolderWithSpaces(gradleVersion: GradleVersion) {
-        project(projectName = "Project Path With Spaces", gradleVersion) {
-            build("build") {
-                assertTasksExecuted(":compileKotlin", ":compileTestKotlin")
-                assertOutputDoesNotContain("Forcing System.gc")
-            }
-        }
-    }
-
     @DisplayName("Logs contain memory usage entries on LIFECYCLE log level")
     @GradleTest
     fun testLogLevelForceGC(gradleVersion: GradleVersion) {

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/Project Path With Spaces/build.gradle

@@ -39,6 +39,12 @@ tasks.test {
     useJUnit {
         exclude("**/*LincheckTest.class")
     }
+    val jdk8Provider = project.getToolchainJdkHomeFor(JdkMajorVersion.JDK_1_8)
+    val jdk11Provider = project.getToolchainJdkHomeFor(JdkMajorVersion.JDK_11_0)
+    doFirst {
+        systemProperty("jdk8Home", jdk8Provider.get())
+        systemProperty("jdk11Home", jdk11Provider.get())
+    }
 }
 
 tasks.register<Test>("lincheckTest") {