Add NSEntityMigrationPolicy to mapping migration

Author: iamgabrielma

Storage/Storage/Model/WooCommerceModelV74toV75.xcmappingmodel/xcmapping.xml

@@ -1,4 +1,4 @@
-<?xml version="1.0"?>
+<?xml version="1.0" standalone="yes"?>
 <!DOCTYPE database SYSTEM "file:///System/Library/DTDs/CoreData.dtd">
 
 <database>
@@ -278,6 +278,7 @@
         <relationship name="entitymapping" type="1/1" destination="XDDEVENTITYMAPPING" idrefs="z791"></relationship>
     </object>
     <object type="XDDEVENTITYMAPPING" id="z150">
+        <attribute name="migrationpolicyclassname" type="string">Storage.DeleteEntityObjectsMigrationPolicy</attribute>
         <attribute name="sourcename" type="string">CustomerSearchResult</attribute>
         <attribute name="mappingtypename" type="string">Undefined</attribute>
         <attribute name="mappingnumber" type="int16">56</attribute>
@@ -1497,13 +1498,14 @@ dmVyVCR0b3BYJG9iamVjdHMSAAGGoF8QD05TS2V5ZWRBcmNoaXZlctEAAAAIAAAACVRyb290gAGvEUYr
         <relationship name="entitymapping" type="1/1" destination="XDDEVENTITYMAPPING" idrefs="z581"></relationship>
     </object>
     <object type="XDDEVENTITYMAPPING" id="z410">
+        <attribute name="migrationpolicyclassname" type="string">Storage.DeleteEntityObjectsMigrationPolicy</attribute>
         <attribute name="sourcename" type="string">Customer</attribute>
         <attribute name="mappingtypename" type="string">Undefined</attribute>
         <attribute name="mappingnumber" type="int16">22</attribute>
         <attribute name="destinationname" type="string">Customer</attribute>
         <attribute name="autogenerateexpression" type="bool">1</attribute>
         <relationship name="mappingmodel" type="1/1" destination="XDDEVMAPPINGMODEL" idrefs="z176"></relationship>
-        <relationship name="attributemappings" type="0/0" destination="XDDEVATTRIBUTEMAPPING" idrefs="z531 z662 z442 z570 z704 z824 z186 z320 z449 z575 z705 z487 z613 z738 z102 z230 z361 z495 z616 z742 z401 z528 z660 z786 z146 z272 z405"></relationship>
+        <relationship name="attributemappings" type="0/0" destination="XDDEVATTRIBUTEMAPPING" idrefs="z705 z401 z786 z186 z704 z495 z660 z528 z824 z405 z531 z361 z442 z449 z570 z662 z230 z616 z738 z487 z146 z613 z575 z742 z272 z102 z320"></relationship>
         <relationship name="relationshipmappings" type="0/0" destination="XDDEVRELATIONSHIPMAPPING" idrefs="z788"></relationship>
     </object>
     <object type="XDDEVATTRIBUTEMAPPING" id="z411">

Storage/StorageTests/CoreData/MigrationTests.swift

@@ -1415,8 +1415,8 @@ final class MigrationTests: XCTestCase {
         // Then
         // After migration, we're deleting the entities and regenerating them due to heavyweight migration
         // in WooCommerceModelV74toV75, as the new ones have siteID
-        XCTAssertEqual(try sourceContext.count(entityName: "Customer"), 0)
-        XCTAssertEqual(try sourceContext.count(entityName: "CustomerSearchResult"), 0)
+        XCTAssertEqual(try targetContext.count(entityName: "Customer"), 0)
+        XCTAssertEqual(try targetContext.count(entityName: "CustomerSearchResult"), 0)
         // Inserting new objects after the migration to confirm the new attributes are correct
         let newCustomer = insertCustomer(to: targetContext, forModel: 75)
         let newCustomerSearchResult = targetContext.insert(