Reuse common call logic for attr assign.
Return correct flag.
Fail JIT for any exception during JIT.
Remove unused runtime param.
Remove unused imports.
Split "booting" flag and do not JIT during boot of runtime.
Remove some unused imports.
Catch up with rename of isBootingRuntime back to isBooting.
Improve JIT logging for target script compile.
We do this check elsewhere.
Don't deopt for "call" calls.
Split out break-in-eval-in-loop case to separate spec.
Implement NonLocalReturn.
Reimplement ClassSuperInstr to leverage InstanceSuper logic.
Implement LexicalSearchConst and clean up shared const logic.
Fix #1969: Make StaticScope and IRScope agree on var slot assignment

* IRBuilder was ignore duplicate "_" args in blocks whereas the parser
  would allocate slots in StaticScope for all of them. This effectively
  led the runtime to allocate DynamicScope with 1 fewer slot than what
  was required because a variable's slot id came from StaticScope
  but # variables for a DynamicScope came from IRScope.

  We are yet to find a way to clean up this static/lexical scope
  duplication/split from the old runtime.

* Added a new spec/regression test.
Move more lazy cacheable invariants into indy call sites.
Update regression spec
Localize method defs for #1969.
Fill out port of check_funcall logic more completely.

This may fix #1976.