Add /system/lib to the search paths for asan

When running with asan, the platform namespace didn't have /system/lib,
but /data/asan/system/lib in its search paths. As a result, clang
runtime libraries like libclang-rt.asan-i686-android.so which are still
in /system/lib cound not be found.

Fixing the problem by adding /system/lib to the search paths after the
asan path.

Bug: 131170196
Test: check if mediaswcodec process is running in aosp_cf_x86_pasan

Change-Id: Iffe5d25613999a00ead5eb03c0efca1d6c9ce012

apex/ld.config.txt

@@ -38,7 +38,8 @@ namespace.default.link.platform.shared_libs = libEGL.so:libGLESv1_CM.so:libGLESv
 namespace.platform.isolated = true
 
 namespace.platform.search.paths = /system/${LIB}
-namespace.platform.asan.search.paths = /data/asan/system/${LIB}
+namespace.platform.asan.search.paths  = /data/asan/system/${LIB}
+namespace.platform.asan.search.paths +=           /system/${LIB}
 
 # /system/lib/libc.so, etc are symlinks to /apex/com.android.lib/lib/bionic/libc.so, etc.
 # Add /apex/... pat to the permitted paths because linker uses realpath(3)