MDEV-4425 Regexp enhancements

Adding tests with 0x00 characters from

Bug#70470 REGEXP fails to find matches after NUL character

mysql-test/r/func_regexp_pcre.result

@@ -414,6 +414,15 @@ SELECT '!' RLIKE '\\S';
 SELECT '.' RLIKE '\\S';
 '.' RLIKE '\\S'
 1
+SELECT 'abc\0def' REGEXP 'def';
+'abc\0def' REGEXP 'def'
+1
+SELECT 'abc\0def' REGEXP 'abc\\x{00}def';
+'abc\0def' REGEXP 'abc\\x{00}def'
+1
+SELECT HEX(REGEXP_SUBSTR('abc\0def','abc\\x{00}def'));
+HEX(REGEXP_SUBSTR('abc\0def','abc\\x{00}def'))
+61626300646566
 #
 # Checking REGEXP_REPLACE
 #

mysql-test/t/func_regexp_pcre.test

@@ -144,6 +144,13 @@ SELECT '1' RLIKE '\\S';
 SELECT '!' RLIKE '\\S';
 SELECT '.' RLIKE '\\S';
 
+# checking 0x00 bytes
+# Bug#70470 REGEXP fails to find matches after NUL character
+SELECT 'abc\0def' REGEXP 'def';
+SELECT 'abc\0def' REGEXP 'abc\\x{00}def';
+SELECT HEX(REGEXP_SUBSTR('abc\0def','abc\\x{00}def'));
+
+
 --echo #
 --echo # Checking REGEXP_REPLACE
 --echo #