Get rid of assumptions about ".nexe" extension.

tests/ppapi_example_gles2/nacl.scons

 # -*- python -*-
 # Copyright (c) 2011 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This is a Pepper 3D (OpenGLES2) example from ppapi/examples/gles2.
 
 Import('env')
 
 env.Prepend(CPPDEFINES=['XP_UNIX'])
 
 env.Append(CPPPATH=['$SOURCE_ROOT/ppapi/lib/gl/include'])
 
-nexe_name = 'ppapi_example_gles2_%s.nexe' % env.get('TARGET_FULLARCH')
+nexe_name = 'ppapi_example_gles2_%s' % env.get('TARGET_FULLARCH')
 nexe = env.ComponentProgram(
     nexe_name,
     ['$SOURCE_ROOT/ppapi/examples/gles2/gles2.cc'],
     EXTRA_LIBS=['${PPAPI_LIBS}', 'ppapi_cpp'])
 
 # Note that the html is required to run this program.
 env.Publish(nexe_name, 'run',
             ['ppapi_example_gles2.html', 'ppapi_example_gles2.nmf'])
 
 test = env.PPAPIBrowserTester('ppapi_example_gles2_test.out',
                               url='ppapi_example_gles2.html',
                               files=env.ExtractPublishedFiles(nexe_name),
                               args=['--enable_experimental_js'])
 
 env.AddNodeToTestSuite(test,
                        ['chrome_browser_tests'],
                        'run_ppapi_example_gles2_test',
                        # TODO(cstefansen): When fixed set to
                        # env.PPAPIBrowserTesterIsBroken().
                        # code.google.com/p/nativeclient/issues/detail?id=1936
                        is_broken=True)