Revert of Add lextab.pyc as an output of the cached_lex_yacc_tables a…

…ction (patchset #1 of https://codereview.chromium.org/463063003/)

Reason for revert:
This CL added the assumption that Python will write the lextab.pyc file. If that's a wrong assumption, which seems to be the case in some situations, the result is that the cached_lex_yacc_tables target never becomes clean, which in turn means that all IDL files are recompiled on each build.

The problem fixed by this CL was cosmetic only, so is not worth the risk.

Original issue's description:
> Add lextab.pyc as an output of the cached_lex_yacc_tables action
> 
> The primary output is lextab.py, but since it is imported, Python also
> writes lextab.pyc. Listing it too as an output means it won't be left
> around by "ninja -t clean" (and not much else, I think.)
> 
> Prior to the patch
>   https://codereview.chromium.org/425953002/
> the result of not having lextab.pyc listed as an output and running
> "ninja -t clean" was a tree that would build correctly, but that would
> always rerun all the IDL code generation scripts, and thus never become
> "clean".
> 
> BUG=397909
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=180142

TBR=haraken@chromium.org,nbarth@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=397909

Review URL: https://codereview.chromium.org/468743003

git-svn-id: svn://svn.chromium.org/blink/trunk@180329 bbb929c8-8fbe-4397-9dbb-9b2b20218538

Source/bindings/scripts/BUILD.gn

@@ -22,7 +22,6 @@ action("cached_lex_yacc_tables") {
   inputs = idl_lexer_parser_files
   outputs = [
     "$bindings_scripts_output_dir/lextab.py",
-    "$bindings_scripts_output_dir/lextab.pyc",
     "$bindings_scripts_output_dir/parsetab.pickle",
   ]
 

Source/bindings/scripts/scripts.gyp

@@ -32,7 +32,6 @@
       ],
       'outputs': [
         '<(bindings_scripts_output_dir)/lextab.py',
-        '<(bindings_scripts_output_dir)/lextab.pyc',
         '<(bindings_scripts_output_dir)/parsetab.pickle',
       ],
       'action': [