Resurrect test_jit_debug.rb

Revert "Temporarily drop test_jit_debug.rb"

This reverts commit 5437d7c879.

Skipped some CIs which were failing previously.

test/ruby/test_jit_debug.rb

@@ -0,0 +1,13 @@
+require_relative 'test_jit'
+
+return unless defined?(TestJIT)
+return if ENV.key?('APPVEYOR')
+return if ENV.key?('RUBYCI_NICKNAME')
+return if ENV['RUBY_DEBUG']&.include?('ci') # ci.rvm.jp
+
+class TestJITDebug < TestJIT
+  def setup
+    # let `#eval_with_jit` use --jit-debug
+    @jit_debug = true
+  end
+end