Use #ifdef instead of #if USE_ASSERT_CHECKING (#10683)

## Problem

USE_ASSERT _CHECKING is defined as empty entity. but it is checked using
#if

## Summary of changes

Replace `#if USE_ASSERT _CHECKING` with `#ifdef USE_ASSERT _CHECKING` as
done in other places in Postgres

Co-authored-by: Konstantin Knizhnik <[email protected]>

Author: knizhnik

pgxn/neon/file_cache.c

@@ -563,8 +563,8 @@ lfc_cache_containsv(NRelFileInfo rinfo, ForkNumber forkNum, BlockNumber blkno,
 
 	LWLockRelease(lfc_lock);
 
-#if USE_ASSERT_CHECKING
-	do {
+#ifdef USE_ASSERT_CHECKING
+	{
 		int count = 0;
 
 		for (int j = 0; j < nblocks; j++)
@@ -574,7 +574,7 @@ lfc_cache_containsv(NRelFileInfo rinfo, ForkNumber forkNum, BlockNumber blkno,
 		}
 
 		Assert(count == found);
-	} while (false);
+	}
 #endif
 
 	return found;

pgxn/neon/pagestore_smgr.c

@@ -916,7 +916,7 @@ prefetch_register_bufferv(BufferTag tag, neon_request_lsns *frlsns,
 {
 	uint64		min_ring_index;
 	PrefetchRequest hashkey;
-#if USE_ASSERT_CHECKING
+#ifdef USE_ASSERT_CHECKING
 	bool		any_hits = false;
 #endif
 	/* We will never read further ahead than our buffer can store. */
@@ -955,7 +955,7 @@ prefetch_register_bufferv(BufferTag tag, neon_request_lsns *frlsns,
 		else
 			lsns = NULL;
 
-#if USE_ASSERT_CHECKING
+#ifdef USE_ASSERT_CHECKING
 		any_hits = true;
 #endif