Update on "[Executorch] Introduce caching cpu memory allocator"

Meant to use this for temp allocator for kernels. Specifically for sdpa, it seems that on iOS there is a significant overhead coming from allocations

Differential Revision: [D85532079](https://our.internmc.facebook.com/intern/diff/D85532079/)

[ghstack-poisoned]

Author: kimishpatel

extension/memory_allocator/malloc_memory_allocator.h

@@ -52,11 +52,7 @@ class MallocMemoryAllocator : public executorch::runtime::MemoryAllocator {
       return nullptr;
     }
 
-    size_t adjusted_size = executorch::extension::utils::get_aligned_size(size, alignment);
-    if (adjusted_size == 0) {
-      return nullptr;
-    }
-    size = adjusted_size;
+    size = executorch::extension::utils::get_aligned_size(size, alignment);
     void* mem_ptr = std::malloc(size);
     if (!mem_ptr) {
       ET_LOG(Error, "Malloc failed to allocate %zu bytes", size);

extension/memory_allocator/targets.bzl

@@ -9,11 +9,9 @@ def define_common_targets():
 
     runtime.cxx_library(
         name = "malloc_memory_allocator",
-        headers = [
-            "memory_allocator_utils.h",
-        ],
         exported_headers = [
             "malloc_memory_allocator.h",
+            "memory_allocator_utils.h",
         ],
         exported_deps = [
             "//executorch/runtime/core:memory_allocator",
@@ -26,14 +24,12 @@ def define_common_targets():
 
     runtime.cxx_library(
         name = "cpu_caching_allocator",
-        headers = [
-            "memory_allocator_utils.h",
-        ],
         srcs = [
             "cpu_caching_malloc_allocator.cpp",
         ],
         exported_headers = [
             "cpu_caching_malloc_allocator.h",
+            "memory_allocator_utils.h",
         ],
         exported_deps = [
             "//executorch/runtime/core:memory_allocator",