test: Move unicode_ut test into lib

This test doesn't belong at the top level. Move it into the lib/
directory, to match its implementation. Rename it to drop the
unnecessary _ut suffix.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Tested-by: Tom Rini <trini@konsulko.com> # rpi_3, rpi_4, rpi_arm64, am64x_evm_a53, am64-sk
diff --git a/test/lib/Makefile b/test/lib/Makefile
index be20bbc..c36c8b0 100644
--- a/test/lib/Makefile
+++ b/test/lib/Makefile
@@ -27,6 +27,7 @@
 obj-$(CONFIG_GETOPT) += getopt.o
 obj-$(CONFIG_CRC8) += test_crc8.o
 obj-$(CONFIG_UT_LIB_CRYPT) += test_crypt.o
+obj-$(CONFIG_$(XPL_)UT_UNICODE) += unicode.o
 obj-$(CONFIG_LIB_UUID) += uuid.o
 else
 obj-$(CONFIG_SANDBOX) += kconfig_spl.o