Add the SQLITE_DIRECT_OVERFLOW_READ compile time option.

FossilOrigin-Name: 2ab14a846727857175eac7961b7338c4d3b417ca

test/pager1.test

@@ -1766,6 +1766,10 @@ do_multiclient_test tn {
 #   + Page 0,
 #   + A page with a page number greater than (2^31-1).
 #
+# These tests will not work if SQLITE_DIRECT_OVERFLOW_READ is defined. In
+# that case IO errors are sometimes reported instead of SQLITE_CORRUPT.
+#
+ifcapable !direct_read {
 do_test pager1-18.1 {
   faultsim_delete_and_reopen
   db func a_string a_string
@@ -1841,6 +1845,7 @@ do_test pager1-18.6 {
   sqlite3 db test.db
   catchsql { SELECT length(x) FROM t1 }
 } {1 {database disk image is malformed}}
+}
 
 do_test pager1-19.1 {
   sqlite3 db ""