Include JIT information in crash reports

Since enabling YJIT or MJIT drastically changes what could go wrong at
runtime, it's good to be front and center about whether they are enabled
when dumping a crash report. Previously, `RUBY_DESCRIPTION` and the
description printed when crashing can be different when a JIT is on.

Introduce a new internal data global, `rb_dynamic_description`, and set
it to be the same as `RUBY_DESCRIPTION` during initialization; use it
when crashing.

 * version.c: Init_ruby_description(): Initialize and use
       `rb_dynamic_description`.
 * error.c: Change crash reports to use `rb_dynamic_description`.
 * ruby.c: Call `Init_ruby_description()` earlier. Slightly more work
       for when we exit right after printing the description but that
       was deemed acceptable.
 * include/ruby/version.h: Talk about how JIT info is not in
      `ruby_description`.
 * test/-ext-/bug_reporter/test_bug_reporter.rb: Remove handling for
       crash description being different from `RUBY_DESCRIPTION`.
 * test/ruby/test_rubyoptions.rb: ditto

Co-authored-by: Nobuyoshi Nakada <nobu@ruby-lang.org>
Co-authored-by: Alan Wu <alanwu@ruby-lang.org>

test/-ext-/bug_reporter/test_bug_reporter.rb

@@ -7,8 +7,6 @@ class TestBugReporter < Test::Unit::TestCase
     omit if ENV['RUBY_ON_BUG']
 
     description = RUBY_DESCRIPTION
-    description = description.sub(/\+MJIT /, '') if defined?(RubyVM::MJIT) && RubyVM::MJIT.enabled?
-    description = description.sub(/\+YJIT /, '') if defined?(RubyVM::YJIT.enabled?) && RubyVM::YJIT.enabled?
     expected_stderr = [
       :*,
       /\[BUG\]\sSegmentation\sfault.*\n/,

test/ruby/test_rubyoptions.rb

@@ -740,7 +740,7 @@ class TestRubyOptions < Test::Unit::TestCase
         -e:(?:1:)?\s\[BUG\]\sSegmentation\sfault.*\n
       )x,
       %r(
-        #{ Regexp.quote(NO_JIT_DESCRIPTION) }\n\n
+        #{ Regexp.quote(RUBY_DESCRIPTION) }\n\n
       )x,
       %r(
         (?:--\s(?:.+\n)*\n)?