Simplify string escapes

Treat backslash as a universal escape character: "\n" is a newline,
backslash escapes any non-alphanumeric character.

This affects some test cases that had "\," standing for backslash-comma.
With the new uniform treatment of backslashes, this needs to be "\\,".

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/suites/test_suite_x509write.data b/tests/suites/test_suite_x509write.data
index bb40029..cd1b0a3 100644
--- a/tests/suites/test_suite_x509write.data
+++ b/tests/suites/test_suite_x509write.data
@@ -163,7 +163,7 @@
 x509_crt_check:"data_files/server5.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca2.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=Polarssl Test EC CA":"01":"20190210144406":"20290210144406":MBEDTLS_MD_SHA256:0:0:"NULL":0:0:1:-1:"":2:0:"data_files/test-ca2.crt"
 
 X509 String to Names #1
-mbedtls_x509_string_to_names:"C=NL,O=Offspark\, Inc., OU=PolarSSL":"C=NL, O=Offspark\, Inc., OU=PolarSSL":0
+mbedtls_x509_string_to_names:"C=NL,O=Offspark\\, Inc., OU=PolarSSL":"C=NL, O=Offspark\\, Inc., OU=PolarSSL":0
 
 X509 String to Names #2
 mbedtls_x509_string_to_names:"C=NL, O=Offspark, Inc., OU=PolarSSL":"":MBEDTLS_ERR_X509_UNKNOWN_OID
@@ -175,10 +175,10 @@
 mbedtls_x509_string_to_names:"C=NL, O=1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456, OU=PolarSSL":"":MBEDTLS_ERR_X509_INVALID_NAME
 
 X509 String to Names #5 (Escape non-allowed characters)
-mbedtls_x509_string_to_names:"C=NL, O=Offspark\a Inc., OU=PolarSSL":"":MBEDTLS_ERR_X509_INVALID_NAME
+mbedtls_x509_string_to_names:"C=NL, O=Offspark\\a Inc., OU=PolarSSL":"":MBEDTLS_ERR_X509_INVALID_NAME
 
 X509 String to Names #6 (Escape at end)
-mbedtls_x509_string_to_names:"C=NL, O=Offspark\":"":MBEDTLS_ERR_X509_INVALID_NAME
+mbedtls_x509_string_to_names:"C=NL, O=Offspark\\":"":MBEDTLS_ERR_X509_INVALID_NAME
 
 Check max serial length
 x509_set_serial_check: