Bug bash: 3.9.0

[CsCherrYY]

cc: @Eskibear

• Build Task in the root gradle project does not get displayed  #1046

1. Download https://docs.gradle.org/current/samples/zips/sample_building_java_applications-groovy-dsl.zip
2. Open Gradle Projects view, wait for configuring, and check tasks in demo project.
3. Can see application, build and distribution and some other take types in the view.
4. Try to run build task under build type in demo project, this task should execute successfully.

• Parallel runnning of gradle task #1045

1. Use project from step 1 of the previous issue
2. In ./app/build.gradle, add the following snippet

task runApp(type: JavaExec) {
  classpath = sourceSets.main.runtimeClasspath
  mainClass = 'demo.App'
}

3. set the following configuration in ./vscode/settings.json:

"gradle.javaDebug": {
    "tasks": [
        "app:runApp",
    ],
}

4. in VS Code setting, set gradle.allowParallelRun to true and gradle.reuseTerminals to off.
5. open App.java in app project, add a breakpoint in main method, e.g. line 12.
6. find runApp task under other type in app project
7. Click Debug task in inline buttons of runApp, the debugging process should stop at the breakpoint.
8. Click Debug task again, you will find another debug process in the CALL STACK view of debugging container.
   
9. Continue debugging, the two processes will finish successfully.

• support dependencies completion in local .m2 folder #990

1. Use project from step 1 of the previous issue
2. In dependencies closure of ./app/build.gradle, try to add a new dependency declaration
3. input implementation("org.spr") and trigger auto-completion manually
4. can find org.springframework.boot in the candidates and choose it.
5. the group id org.springframework.boot will be insert into the declaration with a following :. And the artifact id candidates will be automatically appear.
6. can find spring-boot-starter-web in the candidates, and choose it.
7. the artifact id spring-boot-starter-web will be insert into the declaration with a following :. And the version candidates with updated date information will be automatically appear.
8. choose one version, the text should be inserted into the declaration correctly.

• Hide Gradle commands in non-Gradle workspace #1108

1. open a non-gradle folder, can't find Refresh Gradle Tasks, Run a Gradld Build and Find Gradle Task in the command palette.
2. open a gradle folder, can find the above commands with prefix Gradle: