handle deopt case in builtins properly

[vigneshshanmugam]

• Deopt case was not there for classBody
• handle the case when creating segments when the parentPath is not a function.
• fix babilified code fails at runtime on SystemJS #458
• fix Hoisted or aliased variable issue with webpack #529

[vigneshshanmugam]

will try this with generators if we can avoid full traversal.

[codecov]

Codecov Report

Merging #533 into master will decrease coverage by 0.05%.
The diff coverage is 77.77%.

@@            Coverage Diff            @@
##           master    #533      +/-   ##
=========================================
- Coverage   83.26%   83.2%   -0.06%     
=========================================
  Files          34      34              
  Lines        2539    2549      +10     
  Branches      908     915       +7     
=========================================
+ Hits         2114    2121       +7     
- Misses        254     256       +2     
- Partials      171     172       +1

Impacted Files	Coverage Δ
packages/babel-plugin-minify-builtins/src/index.js	89.79% <77.77%> (-2.25%)	⬇️

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[vigneshshanmugam]

@boopathi This is ready for review now and all the edge cases and included in the test.

[boopathi]

nit: this statement is not required

[boopathi]

in both the above conditions, lastCommon.isProgram() should be false. So, maybe something like this -

let fnParent;
if (!lastCommon.isProgram()) {
  if (lastCommon.isFunction()) {
    segments.set(lastCommon, paths);
    return;
  } else if (!(fnParent = lastCommon.getFunctionParent()).isProgram()) {
    segments.set(fnParent, paths);
    return;
  }
}

[boopathi]

Let's also handle the case where the arrowFn body isn't a block statement.

for example:

function foo() {
  const x = () => Math.max(Math.max(a,b), Math.max(Math.floor(b), Math.floor(c)))
}

[vigneshshanmugam]

Good catch. de-opting for now.