Simplify ifs when branches have condition true/false.
Simplify blocks containing only a variable declaration
and a variable get of the same variable. Simplify to
just the condition.
Do not introduce temporary variables for constants for
null checks. Constants have no side-effects and can be
reloaded freely instead of going through a local.
This simplifies code such as "42.toLong()!!" so that the
resulting code has no branches and uses no locals. The
simplifications happen as follows:
```
block
temp = 42.toLong()
when
(temp == null) throw NPE
(true) load temp
---> null test simplification
block
temp = 42.toLong()
when
(false) throw NPE
(true) load temp
---> when simplification
block
temp = 42.toLong()
load temp
---> block simplification
42.toLong()
```
KT-3894: Loops and finally: finally block executed twice when break and return exists in try/finally block
KT-3874: Compilation error on try catch block contains break and continue
KT-3869: Loops and finally: outer finally block not run
#KT-3869 Fixed
#KT-3894 Fixed
#KT-3874 Fixed
KT-3549 'Finally' block not run when re-throwing exception
KT-3867 When catched exception occurs in finnaly block it invokes additional catch and itself
#KT-3549 Fixed
#KT-3867 Fixed
