Add test case for symbol menu for local enumerators

Add test case for symbol menu for local enumerators

Ada will normally present a menu to the user to allow manual
disambiguation of symbols.  The AdaCore internal GDB had a bug that
prevented this from happening.  Although this bug is not in the FSF
GDB, it seemed worthwhile to write a test case to ensure this.

gdb/testsuite/ChangeLog
2021-01-25  Tom Tromey  <tromey@adacore.com>

	* gdb.ada/local-enum.exp: New file.
	* gdb.ada/local-enum/local.adb: New file.