Now that Exit(X) is supported (0f63626), replace the historical
'Result := X; Exit;' workaround with the Exit(X) function-result shorthand
across compiler, runtime, and stdlib (305 sites).
Only same-indentation pairs are merged: a 'Result := X;' immediately followed
by an 'Exit;' at the same indentation level. Sites where the trailing 'Exit;'
is less-indented than the assignment are left untouched — there the Exit
belongs to an enclosing for/else/if block, not to the assignment, so merging
would change control flow (e.g. the xor/and numeric-result branch in
uSemantic falling through to the Boolean-operand check). 14 such sites are
deliberately not converted.
Three converted sites sit inside a real try/finally (uSemantic overload/
generic resolution); each try body already contained bare Exit; statements
and its finally body is a plain local-list Free, so control flow is unchanged.
A new e2e test (TestRun_ExitValueThroughFinally) confirms Exit(X) from inside
a try/finally runs the finally body and returns the value.
Self-hosting fixpoint verified clean (stage-2 IR == stage-3 IR).