Narrow the check target.

Call GC.verify_internal_consistency only for Gem related test
on i386-solaris.

tool/lib/leakchecker.rb

@@ -11,7 +11,10 @@ class LeakChecker
   end
 
   def check(test_name)
-    GC.verify_internal_consistency if /i386-solaris/ =~ RUBY_PLATFORM
+    if /i386-solaris/ =~ RUBY_PLATFORM && /TestGem/ =~ test_name
+      GC.verify_internal_consistency
+    end
+
     leaks = [
       check_fd_leak(test_name),
       check_thread_leak(test_name),