Gradle

Add continuous build coverage when using composite builds

- Using continuous build with plugin dev

- Using continuous build with multi-project substitutions

- Using continuous build with a simple Java project and library

Add `ProjectRegistry.getRootProject()`

This avoids hard-coding ':' as the root project path in various locations.

Move the files to update configuration to `JavaTestProject`

This allows us reusing the configuration for both performance tests, and the Gradle Profiler.

The `performance.scenarios` file will reuse the same files. There are 2 categories of files to change

for now: `assemble` and `test`.

Release notes adjustments

Rename ExecutionScopeServices to BuildTreeScopeServices

The hierarchy is:

Global < BuildSession < BuildTree < Build < Gradle < Project

Show root cause when transforming exception fails

Instead of showing why the transforming failed we should always show

the original build failure.

Add `performance.scenarios` file to Java performance test projects

Fail when configuring unregistered build cache

Polish integration tests

- Reuse `customDaemonRegistry()`

Remove double canonicalization of project dirs

Polish Javadoc of DirectoryBuildCache

In order to have the default size show up in the DSL docs I needed

to add the size as text. This is since we cannot parse the

constant expression written in the source code in our tooling - and

since 5 GB looks much nicer than 5120 MB.

Since the constant then was unused I just inlined it.

Revert log polling delay to 10ms

Merge branch 'release'

Upgrade the Build Scan Plugin to 1.7.2 and un-ignore related checks

Polish AbstractTask some more

+review REVIEW-6534

Rebaseline performance test

This test has been failing since its introduction. There's no easy way to mitigate the regression,

so we decided to rebaseline for now.

Polish AbstractTask

+review REVIEW-6534

Write end time instead of start time in operation tree.

Attempt to resolve an artifact only once per configuration (including all views of the configuration). If the resolution fails, collect the failure and rethrow when queried again later.

Merge remote-tracking branch 'origin/release'

Conflicts:

subprojects/docs/src/docs/release/notes.md

Better images for release notes

Removed some duplication that is no longer required.