Perf tests: truncate files

Otherwise they take too much space

tests/performance/file_table_function.xml

@@ -32,11 +32,13 @@
     <query>
         INSERT INTO FUNCTION file('test_file', '{format}', 'key UInt64, value UInt64')
         SELECT number, number FROM numbers(10000000)
+        SETTINGS engine_file_truncate_on_insert = 1
     </query>
 
     <query>
         INSERT INTO FUNCTION file('test_file', '{format}', 'key UInt64, value1 UInt64, value2 UInt64, value3 UInt64, value4 UInt64, value5 UInt64')
         SELECT number, number, number, number, number, number FROM numbers(1000000)
+        SETTINGS engine_file_truncate_on_insert = 1
     </query>
 
     <!-- Disabled in 36538, broken now

tests/performance/number_formatting_formats.xml

@@ -33,7 +33,7 @@
     <create_query>CREATE TABLE IF NOT EXISTS table_{format_fast} (x UInt64) ENGINE = File(`{format}`)</create_query>
 
     <query>INSERT INTO table_{format}      SELECT number FROM numbers(10000000) SETTINGS engine_file_truncate_on_insert = 1</query>
-    <query>INSERT INTO table_{format_fast} SELECT number FROM numbers(20000000)</query>
+    <query>INSERT INTO table_{format_fast} SELECT number FROM numbers(20000000) SETTINGS engine_file_truncate_on_insert = 1</query>
 
     <drop_query>DROP TABLE IF EXISTS table_{format}</drop_query>
     <drop_query>DROP TABLE IF EXISTS table_{format_fast}</drop_query>