The patch adopts and reuses the optimizations from the legacy backend.
The optimizations remove useless temporary variables,
statements and simplify generated JS code.
The optimizations can be disabled by `-Xoptimize-generated-js=false`.
Related to KT-51139
Namely:
- Generate debug info for closing braces, which allows the breakpoints
set on closing braces to be hit
- Generate debug info for 'if' and 'try/catch' statements.
KT-46276
- Don't produce mapping for closing bracket in case of expressionBody
- Map Kt*Function declaration into corresponding js fun declaration
- Update test data & add new test
- elvis expression with complex RHS
- destructuring declarations
- decomposition of `var` statement (for example, in case of
inline destructuring functions)
- `is` LHS &&/|| inline fun RHS
- argument assignment to temporary var on inline call site
- assignment of `next()` result to temporary var in `for` expression
- rethrow statement in exception handler
Alexander Korepanov