JPS IC with daemon was not working since
the commit 514635e965
Before that change `IncrementalCompilation.isEnabled`
returned `true` when the corresponding system property was not set.
After the change `isEnabled` returns `true` only if
the system property is set and equals to `"true"`.
The property was never set up for the daemon if `CompilerMode.JPS_COMPILER`
was used (the property was set up in a JPS process or in the daemon in case
it was used with Gradle).
#KT-19414 fixed
Alexey Tsvetkov
f0becd0040