MPL should use the utilization set by the user correctly

[AcKoucher]

Description

Currently there are two controls that handle how utilization varies across runs:

• target_util which handles the inflation of Mixed clusters and whose initial value corresponds to the actual utilization set by the user;
• target_dead_space which handles the inflation of Std Cell clusters and whose initial value comes from the tests made for the paper results (we begin at 5% which doesn't make any sense for our usage);

As we currently don't have multilevel physical hierarchies in our current test suite, we only the latter which means that literally all of our designs with macros are having their macros placed using a unreasonable value of utilization.

Suggested Solution

Use the utilization correctly and have a single control for the utilization sweep.

Additional Context

No response