Fix some failures on posix

Author: slozier

Src/IronPythonTest/Cases/CPythonCasesManifest.ini

@@ -1215,6 +1215,9 @@ Ignore=true # AssertionError: 5 != 4
 [CPython.test_grammar]
 Ignore=true # blocked by https://github.com/IronLanguages/ironpython3/issues/98
 
+[CPython.test_grp]
+Ignore=true # 2 failures
+
 [CPython.test_gzip]
 IsolationLevel=PROCESS # https://github.com/IronLanguages/ironpython3/issues/1440
 

Src/StdLib/Lib/sysconfig.py

@@ -347,6 +347,7 @@ def get_makefile_filename():
 
 
 def _get_sysconfigdata_name():
+    if sys.implementation.name == "ironpython": return "_sysconfigdata"
     return os.environ.get('_PYTHON_SYSCONFIGDATA_NAME',
         '_sysconfigdata_{abi}_{platform}_{multiarch}'.format(
         abi=sys.abiflags,