The "enableIvy" compiler option is the initial implementation
of the Render3 (or Ivy) code generation. This commit enables
generation generating "Hello, World" (example in the test)
but not much else. It is currenly only useful for internal Ivy
testing as Ivy is in development.
PR Close#21427
Due to an overly agressive assert the compiler would generate
an internal error when referencing an enum declared in
namspace.
Fixes#18170
PR Close#20947
This also allows to customize the filePaths in `.ngsummary.json` file
via the new methods `toSummaryFileName` and `fromSummaryFileName`
on the `CompilerHost`.