Move test/bit-test.c to glib/test/ directory

Closes #1434
10 jobs for custom_test in 16 minutes and 39 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Style Check
passed #1342008
check-todos

00:01:01

passed #1342007
style-check-diff

00:01:05

 
  Build
passed #1342011
cross-android_api21_arm64

00:01:57

passed #1342012
cross-android_api28_arm64

00:00:53

passed #1342013
cross-mingw64

00:01:28

passed #1342010
debian-stable-x86_64

00:03:12

passed #1342009
fedora-x86_64

00:13:18

passed #1342014
win32-ps
msys2-mingw32

00:14:18

passed #1342015
win32-ps
vs2017-x64

00:08:42

 
  Coverage
passed #1342016
coverage

00:01:24

76.2%