Raise PegDown parser timeout to 10s

Signed-off-by: Paul Merlin <[email protected]>

Rebase `JavaFirstUsePerformanceTest` test on latest release nightly

Bump to 4.10.2 nightly

Bump to 4.10.1 nightly

Reworded build scan plugin section in release notes

We attempted to coordinate all access to system properties

for maximum security, but that didn't work out because it
also prevented reads from other threads while someone was
holding the lock. This is no longer a problem on Java 9,
but a deadlock is possible on Java 8.

We now only coordinate our own writes and accept that some
3rd party code may use setProperty() and bypass our checks
that way.

Merge pull request gradle#6378 from gradle/eskatos/build-scan-compat/…

…kotlin-dsl-script-compilation-caching

Fix BuildScanPluginCompatibility after Kotlin DSL 1.0-RC3

Rebaseline first use performance test

Final release notes prep for 4.9

Reduce visibility of new task API in release notes