Bug#12856915 VALGRIND FAILURE IN FILESORT/CREATE_SORT_INDEX

Post-push fix:
The functions write_keys() and find_all_keys() may have a slightly
different function signature, depending on compiler/platform/flags.

mysql-test/valgrind.supp

@@ -792,6 +792,9 @@
    fun:row_drop_table_for_mysql
 }
 
+# Note the wildcard in the (mangled) function signatures of
+# write_keys() and find_all_keys().
+# They both return ha_rows, which is platform dependent.
 {
    Bug#12856915 VALGRIND FAILURE IN FILESORT/CREATE_SORT_INDEX / one
    Memcheck:Param
@@ -800,8 +803,8 @@
    fun:my_write
    fun:my_b_flush_io_cache
    fun:_my_b_write
-   fun:_ZL10write_keysP13st_sort_paramPPhjP11st_io_cacheS4_
-   fun:_ZL13find_all_keysP13st_sort_paramP10SQL_SELECTPPhP11st_io_cacheS6_S6_
+   fun:_Z*10write_keysP13st_sort_paramPPhjP11st_io_cacheS4_
+   fun:_Z*13find_all_keysP13st_sort_paramP10SQL_SELECTPPhP11st_io_cacheS6_S6_
    fun:_Z8filesortP3THDP8st_tableP13st_sort_fieldjP10SQL_SELECTybPy
 }