alr get timeout and crash on solving crates

[leogermond]

Checklist

• I've included the output of alr version.
• I've included complete steps to reproduce my issue.

Describe the bug

alr v2.0.1

On an encrypted filesystem on windows, alr is very slow to resolve dependencies of a alr get, which causes a timeout, and ultimately a crash.

PS > alr -nd get -b labs_solar_system
Warning: Exploring incomplete solutions to dependencies, this may take some time...
ERROR: Solver failed to find any solution to fulfill dependencies after 31.10
ERROR: alr encountered an unexpected error, re-run with -d for details.
ERROR: error location: 0x7ff79c210064 Semantic_Versioning.Basic.Restrictions.First_Index at alire-solver.adb:1382

Also it proposed running it with the -d switch which was already set

To Reproduce
Steps to reproduce the behavior:

1. Get your hands on a very slow filesystem
2. Run alr get labs_solar_system
3. See error

Expected Behavior

I would prefer if it asked for continuing like it does when installing the tools:

PS training_labs_solar_system> alr edit
Note: There is no editor currently configured.
Please select your prefered editor or 'other' to enter a custom command
 1. VS Code
 2. GNAT studio
 3. Other
Enter your choice index (first is default):
> 2
Note: 'gnatstudio -P ${GPR_FILE}' is now set as the editor command.
Note: You can change editors by running the following command:
Note: `alr edit --select-editor`
Note: Synchronizing workspace...
Warning: No solution found after 5 seconds.
Do you want to keep solving for a few more seconds?
[Y] Yes [N] No [A] Always (default is Yes) Y
Warning: No solution found after 19 seconds.
Do you want to keep solving for a few more seconds?
[Y] Yes [N] No [A] Always (default is Yes) A
Warning: No solution found after 26 seconds.

alr version

alr v2.0.1 on windows

alr logs

ERROR: Solver failed to find any solution to fulfill dependencies after 31.10
ERROR: alr encountered an unexpected error, re-run with -d for details.
ERROR: error location: 0x7ff79c210064 Semantic_Versioning.Basic.Restrictions.First_Index at alire-solver.adb:1382

[mosteo]

Yes, the crash is clearly a bug. This might be fixed by #1739, to be checked.