gdb/testsuite/dwarf: simplify line number program syntax

By calling `uplevel $body` in the program proc (a pattern we use at many
places), we can get rid of curly braces around each line number program
directive.  That seems like a nice small improvement to me.

Change-Id: Ib327edcbffbd4c23a08614adee56c12ea25ebc0b
26 files changed