First draft of sol vs fe gas benchmarking

[cburgdorf]

$ ./target/debug/fe bench
Found 4 benchmark fixture(s)

--- bitwise_u256 ---
--- loops ---
--- math_u256 ---
--- storage_simple ---
Fixture              Function         Fe/Yul   Fe/Yul+O   Sonatina        Sol      Sol+O   vs Sol+O
----------------------------------------------------------------------------------------------
bitwise_u256         and_              22411      22378      22529      22203      21920      +2.1%
bitwise_u256         or_               22433      22400      22555      22159      21920      +2.2%
bitwise_u256         xor_              22455      22422      22581      22115      21920      +2.3%
bitwise_u256         shl_              22453      22420      22586      22160      21860      +2.6%
bitwise_u256         shr_              22484      22451      22617      22128      21890      +2.6%
loops                counter           34063      34045      33209      80803      51550     -34.0%
loops                sum               38704      38686      35541     129342      71154     -45.6%
loops                xorLoop           41415      40626      38247      86157      57779     -29.7%
loops                counterUnchecked      34129      34111      33287      34957      32584      +4.7%
loops                sumUnchecked      38770      38752      35619      37760      34868     +11.1%
loops                xorLoopUnchecked      41478      40689      38318      40355      38857      +4.7%
math_u256            add               22387      22354      22505      22292      21860      +2.3%
math_u256            sub               22412      22379      22531      22336      21860      +2.4%
math_u256            mul               22433      22400      22559      22421      21860      +2.5%
math_u256            div               22458      22425      22585      22307      21860      +2.6%
math_u256            mod_              22477      22444      22604      22263      21860      +2.7%
storage_simple       store             44340      44317      44348      44106      43749      +1.3%
storage_simple       load              24259      24230      24402      23972      23630      +2.5%
storage_simple       storeAndLoad      44921      44900      45061      44517      43847      +2.4%

Interesting, loops seem to be significantly more gas efficient in Fe.
It's just the missing safemath