Merge branch '2.7' into 2.8

* 2.7:
  move provider after test
  update dataProvider function name
  cast substr result to string and remove empty function use
  rename dataset provider
  Add a test to prevent future regressions
  Switch to `empty` native function to check emptiness
  remove non relevant test case
  Switch to `is_string` native method
  Remove unnecessary parentheses
  Add a test case to prevent future regressions
  Move empty condition in return statement
  Use LF line separator
  fix coding standard to comply with fabbot
  Remove malformed EmailValidatorTest + Update UrlValidator test
  Add empty check on host in other methods + add unit tests
  [Validator] Allow checkMX() to return false when $host is empty
  [DI] Fix the xml schema
  [Translation] avoid creating cache files for fallback locales.

Author: nicolas-grekas

Loader/schema/dic/services/services-1.0.xsd

@@ -145,8 +145,8 @@
   </xsd:complexType>
 
   <xsd:complexType name="property" mixed="true">
-    <xsd:choice minOccurs="0" maxOccurs="1">
-      <xsd:element name="property" type="property" minOccurs="0" maxOccurs="unbounded" />
+    <xsd:choice minOccurs="0">
+      <xsd:element name="property" type="property" maxOccurs="unbounded" />
       <xsd:element name="service" type="service" />
     </xsd:choice>
     <xsd:attribute name="type" type="argument_type" />
@@ -158,8 +158,8 @@
   </xsd:complexType>
 
   <xsd:complexType name="argument" mixed="true">
-    <xsd:choice maxOccurs="unbounded">
-      <xsd:element name="argument" type="argument" minOccurs="0" maxOccurs="unbounded" />
+    <xsd:choice minOccurs="0">
+      <xsd:element name="argument" type="argument" maxOccurs="unbounded" />
       <xsd:element name="service" type="service" />
     </xsd:choice>
     <xsd:attribute name="type" type="argument_type" />
@@ -170,10 +170,9 @@
     <xsd:attribute name="strict" type="boolean" />
   </xsd:complexType>
 
-  <xsd:complexType name="call" mixed="true">
-    <xsd:choice maxOccurs="unbounded">
-      <xsd:element name="argument" type="argument" minOccurs="0" maxOccurs="unbounded" />
-      <xsd:element name="service" type="service" />
+  <xsd:complexType name="call">
+    <xsd:choice minOccurs="0">
+      <xsd:element name="argument" type="argument" maxOccurs="unbounded" />
     </xsd:choice>
     <xsd:attribute name="method" type="xsd:string" />
   </xsd:complexType>