/data/nativetest[64] processes are running with the new ns config

Native tests under /data/nativetest[64] directory is now running with
the same linker namespace configuration as /system/bin/* processes.

This allows us to stop mimicing the linker namespace configuration of the
/system/bin/* processes using LD_LIBRARY_PATH.

Bug: 63597267
Test: run bionic-unit-tests
Test: run linker-unit-tests
Change-Id: If8e2ed0b8016e4e07bf6829735b8e02f952042d0

rootdir/etc/ld.config.txt

@@ -7,6 +7,8 @@
 dir.system = /system/bin/
 dir.system = /system/xbin/
 dir.vendor = /vendor/bin/
+dir.system = /data/nativetest/
+dir.system = /data/nativetest64/
 
 [system]
 additional.namespaces = sphal,vndk,rs