Suffixed memory leak tests as "memory_leak"

So that `TEST_EXCLUDES` option in common.mk works.

test/ruby/test_autoload.rb

@@ -440,8 +440,9 @@ p Foo::Bar
     end
   end
 
-  def test_no_leak
+  def test_no_memory_leak
-    assert_no_memory_leak([], '', <<~'end;', 'many autoloads', timeout: 60)
+    assert_no_memory_leak([], '', "#{<<~"begin;"}\n#{<<~'end;'}", 'many autoloads', timeout: 60)
+    begin;
       200000.times do |i|
         m = Module.new
         m.instance_eval do

test/ruby/test_io.rb

@@ -3913,21 +3913,22 @@ __END__
     end
   end
 
-  def test_select_leak
+  def test_select_memory_leak
     # avoid malloc arena explosion from glibc and jemalloc:
     env = {
       'MALLOC_ARENA_MAX' => '1',
       'MALLOC_ARENA_TEST' => '1',
       'MALLOC_CONF' => 'narenas:1',
     }
-    assert_no_memory_leak([env], <<-"end;", <<-"end;", rss: true, timeout: 60)
+    assert_no_memory_leak([env], "#{<<~"begin;"}\n#{<<~'else;'}", "#{<<~'end;'}", rss: true, timeout: 60)
+    begin;
       r, w = IO.pipe
       rset = [r]
       wset = [w]
       exc = StandardError.new(-"select used to leak on exception")
       exc.set_backtrace([])
       Thread.new { IO.select(rset, wset, nil, 0) }.join
-    end;
+    else;
       th = Thread.new do
         Thread.handle_interrupt(StandardError => :on_blocking) do
           begin

test/ruby/test_symbol.rb

@@ -523,7 +523,7 @@ class TestSymbol < Test::Unit::TestCase
     assert_nothing_raised(NoMethodError, bug10259) {obj.send("unagi=".intern, 1)}
   end
 
-  def test_symbol_fstr_leak
+  def test_symbol_fstr_memory_leak
     bug10686 = '[ruby-core:67268] [Bug #10686]'
     assert_no_memory_leak([], "#{<<~"begin;"}\n#{<<~'else;'}", "#{<<~'end;'}", bug10686, limit: 1.71, rss: true, timeout: 20)
     begin;