Make py import not assume dir is "pnacl-subzero". Avoid autovect in crosstest.

llvm2iceinsts.py

 #!/usr/bin/env python2
 
 import argparse
 import itertools
 import os
 import re
 import subprocess
 import sys
 
-for p in sys.path:
-    if p.endswith('/toolchain_build/src/pnacl-subzero'):
-        sys.path.insert(0, p + '/pydir')
-        break
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), 'pydir'))
 
 from utils import shellcmd
 
 if __name__ == '__main__':
     desc = 'Run llvm2ice on llvm file to produce ICE instructions.'
     argparser = argparse.ArgumentParser(
         description=desc,
         formatter_class=argparse.ArgumentDefaultsHelpFormatter,
         epilog='''
         Runs in two modes, depending on whether the flag '--pnacl' is specified.
@@ skipping 35 matching lines @@
              '--allow-local-symbol-tables', '|']
     cmd += [args.llvm2ice, '-verbose', 'inst', '-notranslate']
     if args.pnacl:
       cmd += ['--allow-local-symbol-tables', '--bitcode-format=pnacl']
     else:
       cmd.append(llfile)
 
     stdout_result = shellcmd(cmd, echo=args.echo_cmd)
     if not args.echo_cmd:
       sys.stdout.write(stdout_result)