test: Add tests for uchar.h #130

Job	Run time
cache-maker	7m 5s
minsize-zephyr (./.github/do-zephyr)	42m 35s
release-zephyr (./.github/do-zephyr)	43m 26s
minsize-zephyr (-Dio-float-exact=false -Dio-long-long=true -Dio-percent-b=true -Dio-long-double=t...	41m 31s
minsize-zephyr (-Dformat-default=integer -Dfreestanding=true -Dposix-io=false -Dnewlib-obsolete-m...	42m 11s
release-zephyr (-Dio-float-exact=false -Dio-long-long=true -Dio-percent-b=true -Dio-long-double=t...	43m 58s
minsize-zephyr (-Dtinystdio=false, ./.github/do-zephyr)	22m 34s
release-zephyr (-Dformat-default=integer -Dfreestanding=true -Dposix-io=false -Dnewlib-obsolete-m...	43m 56s
minsize-zephyr (-Dtinystdio=false -Dnewlib-io-float=true -Dio-long-long=true -Dio-long-double=tru...	20m 47s
release-zephyr (-Dtinystdio=false, ./.github/do-zephyr)	24m 39s
release-zephyr (-Dtinystdio=false -Dnewlib-io-float=true -Dio-long-long=true -Dio-long-double=tru...	23m 52s
	5h 56m 34s

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