libbinder: hide BpBinder::create(*) functions

There is no need to have these around, and having them exposed
potentially means they could be stuck in the ABI.

They are created (instead of absorbed into the private constructors)
because of the additional UID tracking logic there.

Bug: 167966510
Test: binderRpcTest
Change-Id: I673d7a4c591a1b004f3214e8a17b48e54e91171d
diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp
index 9147e23..9f95167 100644
--- a/libs/binder/Parcel.cpp
+++ b/libs/binder/Parcel.cpp
@@ -237,7 +237,7 @@
                     return INVALID_OPERATION;
                 }
             }
-            const int32_t handle = proxy ? proxy->getPrivateAccessorForId().binderHandle() : 0;
+            const int32_t handle = proxy ? proxy->getPrivateAccessor().binderHandle() : 0;
             obj.hdr.type = BINDER_TYPE_HANDLE;
             obj.binder = 0; /* Don't pass uninitialized stack data to a remote process */
             obj.handle = handle;
@@ -572,7 +572,7 @@
     LOG_ALWAYS_FATAL_IF(mData != nullptr, "format must be set before data is written");
 
     if (binder && binder->remoteBinder() && binder->remoteBinder()->isRpcBinder()) {
-        markForRpc(binder->remoteBinder()->getPrivateAccessorForId().rpcSession());
+        markForRpc(binder->remoteBinder()->getPrivateAccessor().rpcSession());
     }
 }