dfa: only goto catch on non-trivial method calls and throws
DfaMemoryStateImpl: introduce unwrap; compare variable values with their non-initialized counterparts
dfa: fighting too complex methods; join complementary memory states after fork to avoid having too many states
dfa: only perform costly state merging when it has chances - after jumps
diagnostics for inconsistencies during control flow building
rebomb test
DfaPsiType: add @NotNull