Delete unused duplicate libc_util.py file (#6579)

## Summary
 
Delete an unused duplicate libc_util.py file. The active version is at
`invokeai/backend/model_manager/libc_util.py`

## QA Instructions

I ran a smoke test to confirm that memory snapshotting still works.

## Merge Plan

- [x] Change target branch to `main` before merging.

## Checklist

- [x] _The PR has a short but descriptive title, suitable for a
changelog_
- [x] _Tests added / updated (if applicable)_
- [x] _Documentation added / updated (if applicable)_

invokeai/backend/model_manager/libc_util.py

@@ -1,75 +0,0 @@
-import ctypes
-
-
-class Struct_mallinfo2(ctypes.Structure):
-    """A ctypes Structure that matches the libc mallinfo2 struct.
-
-    Docs:
-    - https://man7.org/linux/man-pages/man3/mallinfo.3.html
-    - https://www.gnu.org/software/libc/manual/html_node/Statistics-of-Malloc.html
-
-    struct mallinfo2 {
-        size_t arena;     /* Non-mmapped space allocated (bytes) */
-        size_t ordblks;   /* Number of free chunks */
-        size_t smblks;    /* Number of free fastbin blocks */
-        size_t hblks;     /* Number of mmapped regions */
-        size_t hblkhd;    /* Space allocated in mmapped regions (bytes) */
-        size_t usmblks;   /* See below */
-        size_t fsmblks;   /* Space in freed fastbin blocks (bytes) */
-        size_t uordblks;  /* Total allocated space (bytes) */
-        size_t fordblks;  /* Total free space (bytes) */
-        size_t keepcost;  /* Top-most, releasable space (bytes) */
-    };
-    """
-
-    _fields_ = [
-        ("arena", ctypes.c_size_t),
-        ("ordblks", ctypes.c_size_t),
-        ("smblks", ctypes.c_size_t),
-        ("hblks", ctypes.c_size_t),
-        ("hblkhd", ctypes.c_size_t),
-        ("usmblks", ctypes.c_size_t),
-        ("fsmblks", ctypes.c_size_t),
-        ("uordblks", ctypes.c_size_t),
-        ("fordblks", ctypes.c_size_t),
-        ("keepcost", ctypes.c_size_t),
-    ]
-
-    def __str__(self):
-        s = ""
-        s += f"{'arena': <10}= {(self.arena/2**30):15.5f}   # Non-mmapped space allocated (GB) (uordblks + fordblks)\n"
-        s += f"{'ordblks': <10}= {(self.ordblks): >15}   # Number of free chunks\n"
-        s += f"{'smblks': <10}= {(self.smblks): >15}   # Number of free fastbin blocks \n"
-        s += f"{'hblks': <10}= {(self.hblks): >15}   # Number of mmapped regions \n"
-        s += f"{'hblkhd': <10}= {(self.hblkhd/2**30):15.5f}   # Space allocated in mmapped regions (GB)\n"
-        s += f"{'usmblks': <10}= {(self.usmblks): >15}   # Unused\n"
-        s += f"{'fsmblks': <10}= {(self.fsmblks/2**30):15.5f}   # Space in freed fastbin blocks (GB)\n"
-        s += (
-            f"{'uordblks': <10}= {(self.uordblks/2**30):15.5f}   # Space used by in-use allocations (non-mmapped)"
-            " (GB)\n"
-        )
-        s += f"{'fordblks': <10}= {(self.fordblks/2**30):15.5f}   # Space in free blocks (non-mmapped) (GB)\n"
-        s += f"{'keepcost': <10}= {(self.keepcost/2**30):15.5f}   # Top-most, releasable space (GB)\n"
-        return s
-
-
-class LibcUtil:
-    """A utility class for interacting with the C Standard Library (`libc`) via ctypes.
-
-    Note that this class will raise on __init__() if 'libc.so.6' can't be found. Take care to handle environments where
-    this shared library is not available.
-
-    TODO: Improve cross-OS compatibility of this class.
-    """
-
-    def __init__(self):
-        self._libc = ctypes.cdll.LoadLibrary("libc.so.6")
-
-    def mallinfo2(self) -> Struct_mallinfo2:
-        """Calls `libc` `mallinfo2`.
-
-        Docs: https://man7.org/linux/man-pages/man3/mallinfo.3.html
-        """
-        mallinfo2 = self._libc.mallinfo2
-        mallinfo2.restype = Struct_mallinfo2
-        return mallinfo2()