Do not generate TEXT flag if child is constant

Editor assessment

feat(compiler-core) says the TEXT flag is no longer generated when a child is constant. The behavior change is stated clearly and the scope is right, though the type straddles a performance optimization. No body explains the benefit or the assumption behind skipping the flag, which is the substantive question. The subject is imperative and unterminated, with no footers needed. Understandable and valid, but the missing motivation leaves it with little teaching value.