Refactor interpreter selection at pex build time to pass CI

pex/bin/pex.py

@@ -19,6 +19,7 @@
 from pex.base import maybe_requirement
 from pex.common import die, safe_delete, safe_mkdir, safe_mkdtemp
 from pex.crawler import Crawler
+from pex.executor import Executor
 from pex.fetcher import Fetcher, PyPIFetcher
 from pex.http import Context
 from pex.installer import EggInstaller
@@ -534,7 +535,12 @@ def build_pex(args, options, resolver_option_builder):
     # NB: options.python and interpreter constraints cannot be used together, so this will not
     # affect usages of the interpreter(s) specified by the "--python" command line flag
     if ENV.PEX_PYTHON_PATH:
-      interpreters = PythonInterpreter.all(str(ENV.PEX_PYTHON_PATH).split(os.pathsep))
+      interpreters = []
+      for binary in ENV.PEX_PYTHON_PATH.split(os.pathsep):
+        try:
+          interpreters.append(PythonInterpreter.from_binary(binary))
+        except Executor.ExecutionError:
+          pass
     else:
       interpreters = PythonInterpreter.all()
     constraints = options.interpreter_constraint