test_jit.rb: fix typo [ci skip]

we don't have such VM register

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65782 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_jit.rb

@@ -791,7 +791,7 @@ class TestJIT < Test::Unit::TestCase
     end;
   end
 
-  def test_program_pointer_with_regexpmatch
+  def test_program_counter_with_regexpmatch
     assert_eval_with_jit("#{<<~"begin;"}\n#{<<~"end;"}", stdout: "aa", success_count: 1)
     begin;
       2.times do