[committed][gdb/testsuite] Fix gdb.dwarf2/dw2-error.exp with -readnow

[Tom Tromey]

>>>>> "Tom" == Tom de Vries <tdevries@suse.de> writes:

Tom> Hi,
Tom> With test-case gdb.dwarf2/dw2-error.exp and target board readnow, we get:
Tom> ...
Tom> FAIL: gdb.dwarf2/dw2-error.exp: break -q main
Tom> ...

Tom> In the normal case, after running into the dwarf error, the minimal symbols
Tom> are still available, but with -readnow this is not the case.

I didn't understand this explanation.
What's going on here?  Is gdb is rejecting the objfile due to a DWARF
problem?

Tom