simplecov 1.3.1 on Ruby Gems

Bugfixes

cover_views compiles templates on Rails main again. Rails removed ActionView::Template.registered_template_handler; the lookup reads ActionView::Template::Handlers.template_handlers and still skips an extension with no handler. See #1300.
require "simplecov" works again on JRuby on Windows, where 1.3.0 raised LoadError: Could not open library '.../libprism.dll'. Prism's FFI backend cannot open its native library there, and 1.3.0 required Prism as soon as SimpleCov loaded. Prism now loads only when branch or method coverage needs the static extractor, which a line-only run never does. Where it cannot load at all, the extractor falls back to empty branch and method tables for never-loaded files, as it did before 1.3.0. See #1299.
simplecov affected --run works on JRuby on Windows, where it crashed with NoMethodError because Process.wait2 answers no status there. On that platform the runner starts through Kernel#system instead.
simplecov serve refuses a symlink that points outside the report on JRuby on Windows too. JRuby's File.realpath follows no symlinks there, so serve would have served the file the link pointed to, and simplecov clean and the coverage.json lookup compared paths that were never resolved. On JRuby the CLI now resolves paths through the JDK.