A bare or type-qualified enum member (`Color.cRed`, or `cRed` where the
target type is known) now resolves correctly.
Also adds TSymbolTable.InCodegen, set by both backends around code
emission, which disables the analysis-time impl-private suppression in
Lookup. That guard exists only to stop an implementation-section symbol
of unit A leaking into a different unit B DURING ANALYSIS; at codegen a
backend legitimately resolves a unit's own impl-section classes to emit
their typeinfo/vtable/_FieldCleanup. FDefineOwningUnit can drift to a
dependency unit mid-emit, which previously made the suppression wrongly
fire and silently drop an impl-section class's typeinfo — leaving a
dangling `typeinfo_<Unit>_<Class>` reference the linker bound to a garbage
address (an out-of-range-metaclass crash, e.g. via RegisterTest). This
is the robust, both-backend root-cause fix for that crash, which this
commit's layout change re-exposed; it supersedes the narrower
EmitClassSection DefineOwningUnit-pin added earlier.
4d0c7c461d