Load /etc/{passwd,group} from all partitions

Note that unlike the oem_ range that is used for the vendor
partitions, we do not create oem_<n> entries for these new reserved
ranges; they will only appear in getpwent()/getgrent() if there is an
entry in the corresponding passwd/group file.

Bug: 73062966
Test: can load AIDs from partitions other than vendor
Test: bionic-unit-tests
Change-Id: Ifcbbf202894adff948eaaba2a59e25c993611140
diff --git a/libc/bionic/grp_pwd_file.cpp b/libc/bionic/grp_pwd_file.cpp
index 201c9d0..e13604e 100644
--- a/libc/bionic/grp_pwd_file.cpp
+++ b/libc/bionic/grp_pwd_file.cpp
@@ -270,8 +270,8 @@
 
   while (line_beginning < end) {
     line_beginning = ParseLine(line_beginning, end, line->fields, line->kNumFields);
-    // To comply with Treble, users/groups from the vendor partition need to be prefixed with
-    // vendor_.
+    // To comply with Treble, users/groups from each partition need to be prefixed with
+    // the partition name.
     if (required_prefix_ != nullptr) {
       if (strncmp(line->fields[0], required_prefix_, strlen(required_prefix_)) != 0) {
         char name[kGrpPwdBufferSize];