use * for pointer type instead of &

See #770

To help automatically translate code, see the
zig-fmt-pointer-reform-2 branch.

This will convert all & into *. Due to the syntax
ambiguity (which is why we are making this change),
even address-of & will turn into *, so you'll have
to manually fix thes instances. You will be guaranteed
to get compile errors for them - expected 'type', found 'foo'

test/assemble_and_link.zig

@@ -1,7 +1,7 @@
 const builtin = @import("builtin");
 const tests = @import("tests.zig");
 
-pub fn addCases(cases: &tests.CompareOutputContext) void {
+pub fn addCases(cases: *tests.CompareOutputContext) void {
     if (builtin.os == builtin.Os.linux and builtin.arch == builtin.Arch.x86_64) {
         cases.addAsm("hello world linux x86_64",
             \\.text