Bump async-profiler to 2.7-DD-20220303 (DataDog#3423)

Updates in async-profiler since last bump:
* Support for OpenJ9
* Dwarf stack unwinding
* Improve static analysis on CI
* Remove stacktrace field from jdk.ActiveSetting
* Logging improvements

Full diff at https://github.com/datadog/async-profiler/compare/DD-20220212...DD-20220303

* Set default async-profiler set mode to 12

That disables by default problematic stack wingling techniques. They largely
augment the tendency to lead to native crashes.

* Bump async-profiler to 2.7-DD-20220303

https://github.com/datadog/async-profiler/compare/DD-20220301...DD-20220303

Revert "Some gradle cleanup in preparation for 7.x" (DataDog#3347)