[Core] Faster optimizer table by disabling reservation check

[Michaelvll]

Partially fixes #3159

Upper current PR, lower master (1.8s -> 0.5s): the time it takes for starting _launch_with_confirm to confirmation prompt.

On my local laptop, it takes even longer: 127s vs 2s
Upper master, lower currnet PR

The reservation check on GCP causes the optimizer table to show up very slowly. We now disable the check by default, and add a new option to turn on it.

This issue becomes significant when H100 is involved (#3279, need to confirm)

Tested (run the relevant ones):

• Code formatting: bash format.sh
• Any manual or new tests for this PR (please specify below)
• All smoke tests: pytest tests/test_smoke.py
• Relevant individual smoke tests: pytest tests/test_smoke.py::test_fill_in_the_name
• Backward compatibility tests: bash tests/backward_comaptibility_tests.sh

[concretevitamin]

Thanks, seeing >2x speedup on my end too.

Master

sky launch:
5.59, 3.84, 5.64

sky launch --gpus H100:8
3.19, 3.03, 3.17

#3280

sky launch:
2.38, 2.62, 2.21

sky launch --gpus H100:8
1.75, 1.41, 1.44