gdb/testsuite: Match file size in gdb.debuginfod/crc_mismatch.exp

gdb/testsuite: Match file size in gdb.debuginfod/crc_mismatch.exp

gdb's debuginfod progress messages include the size of the file being
downloaded if the size information is available at the time the message
is printed.  For example:

    Downloading 10 MB separate debug info for /lib64/libxyz.so

This size information is omitted if it's not available at the time of
printing:

    Downloading separate debug info for /lib64/libxyz.so

A pattern in crc_mismatch.exp fails to be matched if a progress message
includes a file size.  Add a wildcard to the pattern so that it matches
the progress message whether or not it includes the file size.