[libc++/abi] Re-remove unnecessary null pointer checks from operator delete

In 7cd67904f776, we removed the unnecessary nullptr checks from the libc++abi
definition of operator delete, but we forgot to update the definition in
libc++ (damn code duplication!). Then, in d4a1e03c5fb5, I synced the
definitions across libc++ and libc++abi, but I did it the wrong way around.
I re-added the if() checks to libc++abi instead of removing them from libc++.

In ef74f0fdc339, we re-removed the if() check from operator delete, but
only in libc++abi. This patch corrects this mess and removes it
consistently in libc++ and libc++abi.

Differential Revision: https://reviews.llvm.org/D93473

GitOrigin-RevId: bc556e5685c0f97e79fb7b3c6f15cc5062db8e36
diff --git a/src/stdlib_new_delete.cpp b/src/stdlib_new_delete.cpp
index a3e028b..8ef3057 100644
--- a/src/stdlib_new_delete.cpp
+++ b/src/stdlib_new_delete.cpp
@@ -214,9 +214,7 @@
 operator delete(void* ptr, std::align_val_t) _NOEXCEPT
-    if (ptr) {
-        std::__libcpp_aligned_free(ptr);
-    }
+    std::__libcpp_aligned_free(ptr);