MDEV-23463 fil_page_decompress() debug check wastes 128KiB of stack

fil_page_decompress(): Remove a rather useless debug check.
We should have test coverage for reading page_compressed pages
from files, either due to buffer pool page eviction or due to
server restarts.

A similar check was removed from fil_space_encrypt() in
commit 0b36c27 (MDEV-20307).

storage/innobase/fil/fil0pagecompress.cc

@@ -1,6 +1,6 @@
 /*****************************************************************************
 
-Copyright (C) 2013, 2018, MariaDB Corporation.
+Copyright (C) 2013, 2020, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -243,24 +243,12 @@ UNIV_INTERN ulint fil_page_compress(const byte* buf, byte* out_buf, ulint level,
 	/* Set up the actual payload lenght */
 	mach_write_to_2(out_buf+FIL_PAGE_DATA, write_size);
 
-#ifdef UNIV_DEBUG
-	/* Verify */
 	ut_ad(fil_page_is_compressed(out_buf) || fil_page_is_compressed_encrypted(out_buf));
 	ut_ad(mach_read_from_4(out_buf+FIL_PAGE_SPACE_OR_CHKSUM) == BUF_NO_CHECKSUM_MAGIC);
 	ut_ad(mach_read_from_2(out_buf+FIL_PAGE_DATA) == write_size);
 	ut_ad(mach_read_from_8(out_buf+FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION) == (ulint)comp_method ||
 		mach_read_from_2(out_buf+FIL_PAGE_DATA+FIL_PAGE_COMPRESSED_SIZE) == (ulint)comp_method);
 
-	/* Verify that page can be decompressed */
-	{
-		page_t tmp_buf[UNIV_PAGE_SIZE_MAX];
-		page_t page[UNIV_PAGE_SIZE_MAX];
-		memcpy(page, out_buf, srv_page_size);
-		ut_ad(fil_page_decompress(tmp_buf, page));
-		ut_ad(!buf_page_is_corrupted(false, page, 0, NULL));
-	}
-#endif /* UNIV_DEBUG */
-
 	write_size+=header_len;
 
 	if (block_size <= 0) {

storage/xtradb/fil/fil0pagecompress.cc

@@ -1,6 +1,6 @@
 /*****************************************************************************
 
-Copyright (C) 2013, 2018, MariaDB Corporation.
+Copyright (C) 2013, 2020, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -243,24 +243,12 @@ UNIV_INTERN ulint fil_page_compress(const byte* buf, byte* out_buf, ulint level,
 	/* Set up the actual payload lenght */
 	mach_write_to_2(out_buf+FIL_PAGE_DATA, write_size);
 
-#ifdef UNIV_DEBUG
-	/* Verify */
 	ut_ad(fil_page_is_compressed(out_buf) || fil_page_is_compressed_encrypted(out_buf));
 	ut_ad(mach_read_from_4(out_buf+FIL_PAGE_SPACE_OR_CHKSUM) == BUF_NO_CHECKSUM_MAGIC);
 	ut_ad(mach_read_from_2(out_buf+FIL_PAGE_DATA) == write_size);
 	ut_ad(mach_read_from_8(out_buf+FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION) == (ulint)comp_method ||
 		mach_read_from_2(out_buf+FIL_PAGE_DATA+FIL_PAGE_COMPRESSED_SIZE) == (ulint)comp_method);
 
-	/* Verify that page can be decompressed */
-	{
-		page_t tmp_buf[UNIV_PAGE_SIZE_MAX];
-		page_t page[UNIV_PAGE_SIZE_MAX];
-		memcpy(page, out_buf, srv_page_size);
-		ut_ad(fil_page_decompress(tmp_buf, page));
-		ut_ad(!buf_page_is_corrupted(false, page, 0, NULL));
-	}
-#endif /* UNIV_DEBUG */
-
 	write_size+=header_len;
 
 	if (block_size <= 0) {