stdbit tests: Adhere better to Gnulib naming conventions.
* tests/from-glibc/tst-stdc_bit_ceil.c: Renamed from
tests/tst-stdc_bit_ceil.c.
* tests/from-glibc/tst-stdc_bit_floor.c: Renamed from
tests/tst-stdc_bit_floor.c.
* tests/from-glibc/tst-stdc_bit_width.c: Renamed from
tests/tst-stdc_bit_width.c.
* tests/from-glibc/tst-stdc_count_ones.c: Renamed from
tests/tst-stdc_count_ones.c.
* tests/from-glibc/tst-stdc_count_zeros.c: Renamed from
tests/tst-stdc_count_zeros.c.
* tests/from-glibc/tst-stdc_first_leading_one.c: Renamed from
tests/tst-stdc_first_leading_one.c.
* tests/from-glibc/tst-stdc_first_leading_zero.c: Renamed from
tests/tst-stdc_first_leading_zero.c.
* tests/from-glibc/tst-stdc_first_trailing_one.c: Renamed from
tests/tst-stdc_first_trailing_one.c.
* tests/from-glibc/tst-stdc_first_trailing_zero.c: Renamed from
tests/tst-stdc_first_trailing_zero.c.
* tests/from-glibc/tst-stdc_has_single_bit.c: Renamed from
tests/tst-stdc_has_single_bit.c.
* tests/from-glibc/tst-stdc_leading_ones.c: Renamed from
tests/tst-stdc_leading_ones.c.
* tests/from-glibc/tst-stdc_leading_zeros.c: Renamed from
tests/tst-stdc_leading_zeros.c.
* tests/from-glibc/tst-stdc_trailing_ones.c: Renamed from
tests/tst-stdc_trailing_ones.c.
* tests/from-glibc/tst-stdc_trailing_zeros.c: Renamed from
tests/tst-stdc_trailing_zeros.c.
* tests/from-glibc/tst-stdbit.h: Renamed from tests/tst-stdbit.h.
* tests/from-glibc/support/test-driver.c: Renamed from
tests/support/test-driver.c.
* modules/stdbit-tests (Files, Makefile.am): Update.
* config/srclist.txt: Update.