Recompute density and enthalpy instead of reconstructing #7931

Job	Run time
Build SU2 (asan) (BaseNoMPI-asan)	15m 31s
Build SU2 (asan) (ReverseNoMPI-asan)	44m 19s
Build SU2 (BaseMPI)	13m 15s
Build SU2 (tsan) (BaseOMP-tsan)	11m 30s
Build SU2 (ReverseMPI)	14m 23s
Build SU2 (tsan) (ReverseOMP-tsan)	27m 10s
Build SU2 (ForwardMPI)	11m 16s
Build SU2 (BaseNoMPI)	7m 31s
Build SU2 (ReverseNoMPI)	12m 16s
Build SU2 (ForwardNoMPI)	9m 31s
Build SU2 (BaseOMP)	8m 7s
Build SU2 (ReverseOMP)	14m 40s
Build SU2 (ForwardOMP)	10m 14s
Unit Tests (test_driver)	57s
Regression Tests (vandv.py)	29s
Unit Tests (test_driver_AD)	1m 26s
Regression Tests (tutorials.py)	40s
Unit Tests (test_driver_DD)	48s
Regression Tests (parallel_regression.py)	31s
Regression Tests (parallel_regression_AD.py)	32s
Regression Tests (serial_regression.py)	28s
Regression Tests (serial_regression_AD.py)	34s
Regression Tests (hybrid_regression.py)	29s
Regression Tests (hybrid_regression_AD.py)	28s
Thread Sanitizer Tests (hybrid_regression.py)	1m 4s
Thread Sanitizer Tests (hybrid_regression_AD.py)	1m 4s
Address Sanitizer Tests (serial_regression.py)	1m 16s
Address Sanitizer Tests (serial_regression_AD.py)	1m 6s
	3h 31m 35s

Provide feedback