cleanup: remove commented out debug statement in precompile tests (#2191)

This is a stray commented out line that was left over from debugging.

tests/base_rules/precompile/precompile_tests.bzl

diff --git a/tests/base_rules/precompile/precompile_tests.bzl b/tests/base_rules/precompile/precompile_tests.bzl
index 62659fc..508160a 100644
--- a/tests/base_rules/precompile/precompile_tests.bzl
+++ b/tests/base_rules/precompile/precompile_tests.bzl
@@ -302,7 +302,6 @@
 _tests.append(_test_precompiler_action)
 
 def _test_precompiler_action_impl(env, target):
-    #env.expect.that_target(target).runfiles().contains_exactly([])
     action = env.expect.that_target(target).action_named("PyCompile")
     action.contains_flag_values([
         ("--optimize", "2"),