Fix IDNA matching #6396

Job	Run time
build library (--enable-intelasm --enable-sp-asm)	32s
build library (--disable-asm --enable-mlkem --enable-lms --enable-xmss --enable-mldsa)	33s
build library (--enable-intelasm --enable-sp-asm --enable-mlkem --enable-lms --enable-xmss --enab...	32s
build library (--disable-asm)	32s
build library (--enable-intelasm --enable-sp-asm --enable-all-crypto --enable-mlkem --enable-lms ...	54s
build library (--disable-asm --enable-all-crypto --enable-mlkem --enable-lms --enable-xmss --enab...	49s
	3m 52s

Provide feedback