remove clang3.5 from portability (>5years old compiler)

tools/run_tests/run_tests.py

@@ -478,10 +478,6 @@ class CLanguage(object):
             return ('buster', [])
         elif compiler == 'gcc_musl':
             return ('alpine', [])
-        elif compiler == 'clang3.5':
-            return ('jessie',
-                    self._clang_cmake_configure_extra_args(
-                        version_suffix='-3.5'))
         elif compiler == 'clang3.6':
             return ('ubuntu1604',
                     self._clang_cmake_configure_extra_args(
@@ -1451,7 +1447,7 @@ argp.add_argument(
     '--compiler',
     choices=[
         'default', 'gcc4.9', 'gcc5.3', 'gcc7.4', 'gcc8.3', 'gcc_musl',
-        'clang3.5', 'clang3.6', 'clang3.7', 'python2.7', 'python3.5',
+        'clang3.6', 'clang3.7', 'python2.7', 'python3.5',
         'python3.6', 'python3.7', 'python3.8', 'pypy', 'pypy3', 'python_alpine',
         'all_the_cpythons', 'electron1.3', 'electron1.6', 'coreclr', 'cmake',
         'cmake_vs2015', 'cmake_vs2017'

tools/run_tests/run_tests_matrix.py

@@ -275,7 +275,7 @@ def _create_portability_test_jobs(extra_args=[],
 
     # portability C and C++ on x64
     for compiler in [
-            'gcc4.9', 'gcc5.3', 'gcc7.4', 'gcc8.3', 'gcc_musl', 'clang3.5',
+            'gcc4.9', 'gcc5.3', 'gcc7.4', 'gcc8.3', 'gcc_musl',
             'clang3.6', 'clang3.7'
     ]:
         test_jobs += _generate_jobs(languages=['c', 'c++'],