Turn off AOT by default

Summary

Turn off AOT by default and make related flags experimental to reflect that JEP 295 AOT is still experimental.

Problem

The AOT feature is experimental, which implies it should not have any impact for users not interested in or unaware of the same. At present the related command line options UseAOT, AOTLibrary, and PrintAOT are product flags and UseAOT is enabled by default, which leads it can have a performance impact.

Solution

• Change the related flags UseAOT, PrintAOT, and AOTLibrary to experimental type.
• Turn off UseAOT by default.

Specification

The following flags are made experimental in JDK 13u: UseAOT, PrintAOT, and AOTLibrary. Default value of UseAOT is changed from enabled to disabled.