Minor initialization optimizations for TypeInfo and PropertyInfo

Remove some overhead from the initialization. For details, see the individual commit messages.

With these additional changes (on top of !130 (closed)), initialization "overhead" is lower than current release (KF 6.0.0), for all cases.

Note, the overhead is measurable at best, with and without these changes - total instruction count of _dl_init and below went down from ~120.000 instructions to ~110.000 instructions, including all symbol lookup overhead (which is amortized over all users in any non-trivial program).

For comparison, propertyinfotest_bin --help needs about 14M instructions for just starting up, baloosearch --help is at about 40M instructions, and these are probably the most trivial examples possible.

On the other hand, prior to these series a single invocation of TypeInfo::fromName(...) takes ~50000 instructions.