filter TracePoint :line events by file

in target_thread test to avoid such failure:

```
1) Failure:
  TestSetTraceFunc#test_enable_target_thread [/tmp/ruby/src/trunk/test/ruby/test_settracefunc.rb:2595]:
  <[#<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>]> expected but was
  <[#<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>,
   #<Thread:0x000078ca3d778460 run>]>.
```

Author: ko1

test/ruby/test_settracefunc.rb

@@ -2583,6 +2583,7 @@ def test_script_compiled
   def test_enable_target_thread
     events = []
     TracePoint.new(:line) do |tp|
+      next unless tp.path == __FILE__
       events << Thread.current
     end.enable(target_thread: Thread.current) do
       _a = 1
@@ -2596,6 +2597,7 @@ def test_enable_target_thread
 
     events = []
     tp = TracePoint.new(:line) do |tp|
+      next unless tp.path == __FILE__
       events << Thread.current
     end