docs: suggest building partition-alloc, not partition-alloc-padding

docs/build_instructions.md

@@ -50,7 +50,7 @@ cmake ..                                                   \
 - `pad-tls` - builds the pad-tls script.  Only required for compartmentalized DSOs that use thread-local storage.
 - `tools` - builds both `ia2-rewriter` and `pad-tls` (NOTE: does not always detect when to rebuild accurately).
 - `libia2` - builds the runtime as a static library. This does not include call gate transitions as those are program-specific and generated by the rewriter.
-- `partition-alloc-padding` - builds the compartment-aware shim for Chromium's PartitionAlloc allocator.
+- `partition-alloc` - builds the compartment-aware shim for Chromium's PartitionAlloc allocator.
 - `ia2-sandbox` - builds the syscall tracer.
 
 Tests are enumerated in [`tests/CMakeLists.txt`](../tests/CMakeLists.txt). To build a specific test, use `$TEST` as the target. See the [`directory structure doc`](directory_structure.md) for an overview of the rest of the repo's contents.