Original `ComponentRegistrar` exposes Project to its registration method,
so plugins should manually register extensions to it. To prepare for
possible unbound compiler from Project API in future new `K2ComponentRegistrar`
introduced which provides registration method without Project at all
#KT-25128 Fixed
ABI class generation is implemented as a compiler plugin.
Command-line usage:
1. Add a path to 'jvm-abi-gen.jar' to the plguin classpath argument
(`-Xplugin`). By default the jar is located at
'kotlinc/lib/jvm-abi-gen.jar' in the kotlinc distribution archive.
2. Specify an output directory for ABI classes via
`-Pplugin:org.jetbrains.kotlin.jvm.abi:outputDir=<DIR>`.