Work around test failures on red-hat linux

Two tests were failing because the debugger was picking up multiply
defined internal symbols from the system libraries. This is a bug, as
there should be no ambiguity because the tests are defining variables
with should shadow these symbols, but lldb is not smart enough to figure
that out.

I work around the issue by renaming the variables in these tests, and in
exchange I create a self-contained test which reproduces the issue
without depending on the system libraries.

This increases the predictability of our test suite.

llvm-svn: 321271