[clang] Remove hasValue() check in `RecordExprEvaluator::VisitCXXConstructExpr()` (#154610)
When initializing an anonymous struct via an `IndirectFieldDecl`, we
create an `APValue` for the struct, but we leave the fields
uninitialized. This would later cause the `CXXConstructExpr` that
initializes the anonymous struct member to not do anything since its
`APValue` already had a value (but the member didn't). Just remove the
check for an `APValue` that already has a value from
`RecordExprEvaluator::VisitCXXConstructExpr()`.
Fixes #154567