meson: drop convenience library that was only used in one place

It doesn't make much sense to do this, the result is very similar to including
to objects directly in the output binary without going through an intermediate
target.

The linkage of test-libudev was rather strange too: udev_link_with is used to
allow udev to be linked to a static version of libshared, so that udev is not
linked to libshared.so. But here we were using both, defeating the purpose of
udev_link_with. I don't think it matters what the test is linked to, so let's
use the non-static linkage to save space.

src/libudev/meson.build

@@ -31,12 +31,6 @@ libudev_basic = static_library(
         c_args : ['-fvisibility=default'],
         build_by_default : false)
 
-libudev_static = static_library(
-        'udev_static',
-        include_directories : includes,
-        link_with : udev_link_with,
-        link_whole : libudev_basic)
-
 static_libudev = get_option('static-libudev')
 static_libudev_pic = static_libudev == 'true' or static_libudev == 'pic'
 
@@ -53,5 +47,5 @@ custom_target(
 tests += [
         [['src/libudev/test-libudev.c'],
          [libshared,
-          libudev_static]],
+          libudev_basic]],
 ]