Use wrapper distribution when gradle-wrapper.properties exists.

[jdneo]

In GradleProjectImporter, the previously implementation will use GradleDistribution.fromBuild() when the gradlew exists.

While checking the source of Gradle, the Gradle tooling api will check gradle/wrapper/gradle-wrapper.properties instead of the gradlew.

See:

• https://github.com/gradle/gradle/blob/592f269cc959c3620413391e1dad68695e7adad2/platforms/ide/tooling-api/src/main/java/org/gradle/tooling/internal/consumer/DefaultGradleConnector.java#L169C48-L169C70
• https://github.com/gradle/gradle/blob/592f269cc959c3620413391e1dad68695e7adad2/platforms/ide/tooling-api/src/main/java/org/gradle/tooling/internal/consumer/DistributionFactory.java#L59C59-L59C59
• https://github.com/gradle/gradle/blob/592f269cc959c3620413391e1dad68695e7adad2/platforms/core-runtime/wrapper-shared/src/main/java/org/gradle/wrapper/WrapperExecutor.java#L41

This PR changes the logic to use wrapper distribution (GradleDistribution.fromBuild()) when gradle/wrapper/gradle-wrapper.properties exists.

Meanwhile, this PR moves the gradle wrapper jar checksum validation into a non-blocking job, because tooling api will not use that jar to import the project. So, it's not necessary to do it during import synchronized.

[testforstephen]

LGTM.

Checking the gradle-wrapper.properties file is the correct approach to enable the gradle wrapper importer. This file tells the tooling api where to get the gradle distribution from the distributionUrl. The tooling api will download the distribution using its own download utility. It doesn't depend on the local gradle-wrapper.jar for downloading, so it's ok to move the checksum validator to a separate job.

[snjeza]

Meanwhile, this PR moves the gradle wrapper jar checksum validation into a non-blocking job, because tooling api will not use that jar to import the project. So, it's not necessary to do it during import synchronized.

The gradle tooling API doesn't use gradle-wrapper.jar - https://github.com/gradle/gradle/blob/dc132c9b9b14ab88545cdceac90259ecd1ae1198/platforms/core-runtime/wrapper-shared/src/main/java/org/gradle/wrapper/BootstrapMainStarter.java#L45
We could remove the gradle wrapper jar checksum validation.

[rgrunber]

Feel free to merge when ready. Placing the code into a Job would normally open it up to progress reporting, but since no monitor is used, it should be silent, which is fine.

Update: It does report, but it's nothing major.

[Trace - 17:48:53] Received notification '$/progress'.
Params: {
    "token": "35218318-2d27-46a6-9d55-bf30bd6d7f63",
    "value": {
        "kind": "begin",
        "title": "Validating Gradle wrapper checksum...",
        "message": "Validating Gradle wrapper checksum..."
    }
}


[Trace - 17:49:09] Received notification '$/progress'.
Params: {
    "token": "35218318-2d27-46a6-9d55-bf30bd6d7f63",
    "value": {
        "kind": "end",
        "message": "Validating Gradle wrapper checksum..."
    }
}

[jdneo]

We could remove the gradle wrapper jar checksum validation.

This requires to remove java.imports.gradle.wrapper.checksums at vscode-java. I think we need to check some data first to see the usage.