[test] Run TestLaunchWithShellExpand with /bin/sh on POSIX.

Now that we do shell expansion on POSIX with the user's shel, this test
can potentially fail. This should ensure that we always use /bin/sh.

llvm-svn: 373804

lldb/packages/Python/lldbsuite/test/commands/process/launch-with-shellexpand/TestLaunchWithShellExpand.py

@@ -2,6 +2,7 @@
 Test that argdumper is a viable launching strategy.
 """
 from __future__ import print_function
+import os
 
 
 import lldb
@@ -36,6 +37,9 @@ class LaunchWithShellExpandTestCase(TestBase):
             'break here', lldb.SBFileSpec("main.cpp", False))
         self.assertTrue(breakpoint, VALID_BREAKPOINT)
 
+        # Ensure we do the expansion with /bin/sh on POSIX.
+        os.environ["SHELL"] = '/bin/sh'
+
         self.runCmd(
             "process launch -X true -w %s -- fi*.tx? () > <" %
             (self.getSourceDir()))