* Consolidate contiguous var declarations in destructuring transform
Fixes#3081.
* Simplify var node coalescing in es2015-destructuring
* Revert "Simplify var node coalescing in es2015-destructuring"
This reverts commit 15cb373f0726f68225f7080a7ae206a63af174ee.
* More careful condition for var coalescing in es2015-destructuring
* Flip default parameter template
YMMV, I saved ~10b on a 2kb library. Not noticeable at the small scale, by why not do it anyway?
I've (unscientifically) found that flipping the default parameter conditional yields better gzip results. I think this is due to the slightly longer string it can now repeatedly match:
```js
// old
var param = arguments.length <= 0 || void 0 === arguments[0] ? null : arguments[0]
--------------------------------------------------------------^
// new
var param = arguments.length > 1 && void 0 !== arguments[1] ? arguments[1] : null
------------------------------------------------------------------------^
```
Though it's entirely likely gzip will also choose up to the index of the arguments if you many default parameters at different indexes.
* Update tests
* Fix destructuring evaluation with call expressions
Do not optimize destructions with callExpressions, as the call
might change the value of a variable that we are assigning to.
Fixes#4054
* Also deopt on member expressions
members expressions might be getters who have side effects
