JUCE no longer depends on built artifacts of the AAX_SDK

When building for arm64 with a VS generator on a x86_64 host,
CMAKE_CROSSCOMPILING is not set, and copying the generator platform can
result in a juceaide binary that doesn't run on the host system.

The removed code no longer seems to be necessary when configuring with
newer Clion versions.

The ARA_SDK contains unguarded is_lock_free calls. This change
allows us to enable ARA compilation on Linux.

This issue made hosts not recognize the ARA capabilities of AU plugins.

This also fixes an issue where the requested font style could be
incorrectly overwritten.