.exp files were updated to correspond to GDB 15,
filter_gdb being responsible to transform old GDB output to newly
expected output.
Sadly, I edited filter_gdb instead of filter_gdb.in
Tests should succeed again with older GDB.
# Anonymise pid numbers
s/pid [0-9][0-9]*/pid ..../g
+# Align the 'delete' prompt to the GDB 15 prompt
+s/Delete all breakpoints?/Delete all breakpoints, watchpoints, tracepoints, and catchpoints?/
+
+# Align the 'remote failure reply' string to the GDB 15 behaviour.
+s/remote failure reply 'E\./remote failure reply '/
+
# filter 'remote target killed' messages (produced by gdb >= 8.2)
/(Remote target) killed/d