transformers no longer ignore UnApply.fun

Second time's the charm. I remember trying to do exactly the same somewhen
around 2.10.0-M4, but then some continuations tests were failing.
Luckily, today everything went smoothly.

Please note that this fix changes the way that SI-5465 manifests itself.
Previously it produced type errors, now it simply crashes the compiler.
Therefore I had to attach the try/catch FatalError clause to invocations
of toolbox methods, so that compiler crashes get caught and translated to
ToolBoxErrors.

Also fixes SI-7871, and that clears the way for implementing quasiquotes
with conventional macros rather than relying on a special case in typer.
fix minor regression in quasiquote reification

emptyValDef should always be reified as emptyValDef. After the the
introduction of SyntacticValDef this ceased to be true.
harden test case to avoid parsing failure when name is keyword
refactor out common logic between various statSeq-s in parser

Partial functions are left outside of the call to statSeq to allow
re-use and overriding capabilities for quasiquotes.
refactor out range position utility constructors

This will help to re-use same logic for creating range positions even
if atPos isn't used to assign position to the tree.
SI-6841 SI-6657 add support for packages into quasiquotes and toolbox

In order to implement this a new parser entry point
`parseStatsOrPackages` that augments current parseStats with ability
to parse "package name { ... }" syntax.
minor changes due to typos
freedom and equality