scripts: Dropped -e/--exec shortform flag, now just --exec

Too much room for confusion, and potential flag conflicts in the future.
Note it already conflicted with -e/--error-* flags.

--exec is a rather technical flag anyways, and will probably be wrapped
in other ci/script scaffolding most of the time.

scripts/bench.py

@@ -1715,7 +1715,7 @@ if __name__ == "__main__":
             help="Paths to scripts to execute when dropping into gdb. "
                 "Defaults to %r." % GDB_SCRIPTS)
     bench_parser.add_argument(
-            '-e', '--exec',
+            '--exec',
             type=lambda e: e.split(),
             help="Run under another executable.")
     bench_parser.add_argument(

scripts/test.py

@@ -1750,7 +1750,7 @@ if __name__ == "__main__":
             help="Paths to scripts to execute when dropping into gdb. "
                 "Defaults to %r." % GDB_SCRIPTS)
     test_parser.add_argument(
-            '-e', '--exec',
+            '--exec',
             type=lambda e: e.split(),
             help="Run under another executable.")
     test_parser.add_argument(