Remove loaded limits for int128 and address

[charles-cooper]

What I did

Fix #2453

How I did it

How to verify it

Check tests. Also check out where variables start from, reduces gas usage somewhat.

@external
def foo():
    x: uint256 = 1

before

after

Description for the changelog

Cute Animal Picture

[codecov-commenter]

Codecov Report

Merging #2506 (e36417e) into master (cec2c53) will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2506      +/-   ##
==========================================
+ Coverage   84.63%   84.68%   +0.05%     
==========================================
  Files          94       93       -1     
  Lines        9273     9252      -21     
  Branches     2093     2089       -4     
==========================================
- Hits         7848     7835      -13     
+ Misses        940      934       -6     
+ Partials      485      483       -2     

Impacted Files	Coverage Δ
vyper/builtin_functions/convert.py	75.22% <100.00%> (+0.11%)	⬆️
vyper/builtin_functions/functions.py	88.91% <100.00%> (-0.07%)	⬇️
vyper/old_codegen/parser_utils.py	82.78% <100.00%> (ø)
vyper/utils.py	84.76% <100.00%> (-0.40%)	⬇️
vyper/lll/optimizer.py	85.35% <0.00%> (+1.27%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update cec2c53...e36417e. Read the comment docs.