Use gnueabihf for ARM + enabled corelib/isolate/lib/standalone tests on ARM again

tools/gyp/configurations_make.gypi

 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 {
   'variables': {
     'arm_cross_libc%': '/opt/codesourcery/arm-2009q1/arm-none-linux-gnueabi/libc',
     'dart_debug_optimization_level%': '2',
   },
   'target_defaults': {
@@ skipping 33 matching lines @@
         'ldflags': [ '-m32', ],
       },
 
       'Dart_arm_Base': {
         'target_conditions': [
         ['_toolset=="target"', {
           'cflags': [
             '-marm',
             '-march=armv7-a',
             '-mfpu=vfp',
-            '-mfloat-abi=softfp',
             '-Wno-psabi', # suppresses va_list warning
             '-fno-strict-overflow',
           ],
           'ldflags': ['-static'],
         }],
         ['_toolset=="host"', {
           'cflags': ['-m32', '-msse2'],
           'ldflags': ['-m32'],
         }]]
       },
@@ skipping 24 matching lines @@
           '-fno-omit-frame-pointer',
         ],
       },
 
       'Dart_Release': {
         'cflags': [ '-O3', ],
       },
     },
   },
 }