vlib,cgen: cleanup array inits using `.repeat() instead of new init syntax

vlib/builtin/bare/.checks/forkedtest/forkedtest.v

@@ -7,7 +7,7 @@ pub fn run (op fn(), label string, code Wi_si_code, status int) int {
 		sys_exit(0)
 	}
 
-	siginfo := [0].repeat(int(Sig_index.si_size))
+	siginfo := []int{len:int(Sig_index.si_size)}
 
 	e := sys_waitid(.p_pid, child, intptr(&siginfo[0]), .wexited, 0)
 

vlib/builtin/bare/.checks/linuxsys/linuxsys.v

@@ -40,7 +40,7 @@ fn check_read_write_pipe() {
 	//		sys_read
 	//		sys_close
 	//
-	buffer0 := [byte(0)].repeat(128)
+	buffer0 := []byte{len:(128)}
 	buffer := byteptr(buffer0.data)
 
 	fd := [-1, -1]
@@ -87,7 +87,7 @@ fn check_read_file() {
 			sys_close
 			sys_open
 	*/
-	buffer0 := [byte(0)].repeat(128)
+	buffer0 := []byte{len:(128)}
 	buffer := byteptr(buffer0.data)
 
 	test_file := "sample_text1.txt"

vlib/builtin/bare/.checks/string/string.v

@@ -8,7 +8,7 @@ fn check_string_eq () {
 }
 
 fn check_i64_tos() {
-	buffer0 := [byte(0)].repeat(128)
+	buffer0 := []byte{len:(128)}
 	buffer := byteptr(buffer0.data)
 
 	s0 := i64_tos(buffer, 70, 140, 10)