fuzz packaging: implement system/vendor split

This wasn't needed when fuzzers had their own
lib directories, but because the lib directories
were combined, this caused interactions because
system and vendor libraries were mixed in the
same folder, sometimes overriding each other.

Comments are left with some details about
future issues. Bug has a series of recommendations
to prevent issue again.

The main goal of this patch is to get the fuzzers
working, not fix every issue here.

Bug: 307611931
Test: run vendor fuzzer and check lsof:

    android.hardwar 22719       root  txt       REG             254,94   4350056       3455 /data/fuzz/x86_64/android.hardware.drm-service.<name>.aidl_fuzzer/vendor/android.hardware.drm-service.<name>.aidl_fuzzer
    android.hardwar 22719       root  mem       REG             254,94   4350056       3455 /data/fuzz/x86_64/android.hardware.drm-service.<name>.aidl_fuzzer/vendor/android.hardware.drm-service.<name>.aidl_fuzzer
    android.hardwar 22719       root  mem       REG             254,94   1047232       3464 /data/fuzz/x86_64/lib/vendor/libbase.so
    android.hardwar 22719       root  mem       REG             254,94   4027304       3460 /data/fuzz/x86_64/lib/vendor/libcrypto.so
    android.hardwar 22719       root  mem       REG             254,94   4021632       3467 /data/fuzz/x86_64/lib/vendor/libbinder.so
    android.hardwar 22719       root  mem       REG             254,94    329408       3466 /data/fuzz/x86_64/lib/vendor/libcutils.so
    android.hardwar 22719       root  mem       REG             254,94    508968       3463 /data/fuzz/x86_64/lib/vendor/libutils.so
    android.hardwar 22719       root  mem       REG             254,94    592944       3465 /data/fuzz/x86_64/lib/vendor/libclang_rt.ubsan_standalone-x86_64-android.so
    android.hardwar 22719       root  mem       REG             254,94   2328616       3462 /data/fuzz/x86_64/lib/vendor/libc++.so

and run a system fuzzer

    servicemanager_ 27878       root  txt       REG             254,94    609736      67408 /data/fuzz/x86_64/servicemanager_fuzzer/servicemanager_fuzzer
    servicemanager_ 27878       root  mem       REG             254,94    609736      67408 /data/fuzz/x86_64/servicemanager_fuzzer/servicemanager_fuzzer
    servicemanager_ 27878       root  mem       REG             254,94   4390560       4074 /data/fuzz/x86_64/lib/libvintf.so
    servicemanager_ 27878       root  mem       REG             254,94     13872       4077 /data/fuzz/x86_64/lib/libvndksupport.so
    servicemanager_ 27878       root  mem       REG             254,94     13872       4077 /data/fuzz/x86_64/lib/libvndksupport.so
    servicemanager_ 27878       root  mem       REG             254,94     13872       4077 /data/fuzz/x86_64/lib/libvndksupport.so
    servicemanager_ 27878       root  mem       REG             254,94     11584       4086 /data/fuzz/x86_64/lib/libdl.so

and run a system fuzzer

    servicemanager_ 27878       root  txt       REG             254,94    609736      67408 /data/fuzz/x86_64/servicemanager_fuzzer/servicemanager_fuzzer
    servicemanager_ 27878       root  mem       REG             254,94    609736      67408 /data/fuzz/x86_64/servicemanager_fuzzer/servicemanager_fuzzer
    servicemanager_ 27878       root  mem       REG             254,94   4390560       4074 /data/fuzz/x86_64/lib/libvintf.so
    servicemanager_ 27878       root  mem       REG             254,94     13872       4077 /data/fuzz/x86_64/lib/libvndksupport.so
    servicemanager_ 27878       root  mem       REG             254,94     13872       4077 /data/fuzz/x86_64/lib/libvndksupport.so
    servicemanager_ 27878       root  mem       REG             254,94     13872       4077 /data/fuzz/x86_64/lib/libvndksupport.so
    servicemanager_ 27878       root  mem       REG             254,94     11584       4086 /data/fuzz/x86_64/lib/libdl.so

Change-Id: I91a51d2f1cb537cfaae8379998078188f2b10a98