gdb/testsuite: fix copy & paste error in gdb.python/py-format-address.exp

gdb/testsuite: fix copy & paste error in gdb.python/py-format-address.exp

The test gdb.python/py-format-address.exp, added in commit:

  commit 25209e2c6979c3838e14e099f0333609810db280
  Date:   Sat Oct 23 09:59:25 2021 +0100

      gdb/python: add gdb.format_address function

included 3 copy & paste errors where the wrong address was used in the
expected output patterns.

The test compiles two almost identical test binaries (one function
changes its name, that's the only difference), two inferiors are
created, each inferior using one of the test binaries.

We then take the address of the name changing function in both
inferiors ('foo' in inferior 1 and 'bar' in inferior 2) and the tests
are carried out using these addresses.

What we're checking for is that symbols 'foo' and 'bar' show up in the
correct inferior, and that (as this test is for a Python API feature),
the user can have one inferior selected, but ask about the other
inferior, and see the correct symbol in the result.

The hope is that the two binaries will be laid out identically by the
compiler, and that 'foo' and 'bar' will be at the same address.  This
is fine, unless the executable is compiled as PIE (position
independent executable), in which case there is a problem.

The problem is that though inferior 1 is set running, the inferior 2
never is.  If the executables are compiled as PIE, then the address in
the inferior 2 will not have been resolved, while the address in the
inferior 1 will have been, and so the two addresses we use in the
tests will be different.

This issue was reported here:

  https://sourceware.org/pipermail/gdb-patches/2022-March/186911.html

The first part of the fix is to use the correct address variable in
the expected output patterns, with this change the tests pass even
when the executables are compiled as PIE.

A second part of this fix is to pass the 'nopie' option when we
compile the tests, this should ensure that the address obtained in
inferior 2 is the same as the address from inferior 1, which makes the
test more useful.