add regression test for alignment of constants

closes #1741

Author: andrewrk

test/stage1/behavior.zig

@@ -24,6 +24,7 @@ comptime {
     _ = @import("behavior/bugs/1500.zig");
     _ = @import("behavior/bugs/1607.zig");
     _ = @import("behavior/bugs/1735.zig");
+    _ = @import("behavior/bugs/1741.zig");
     _ = @import("behavior/bugs/1851.zig");
     _ = @import("behavior/bugs/1914.zig");
     _ = @import("behavior/bugs/2006.zig");

test/stage1/behavior/bugs/1741.zig

@@ -0,0 +1,6 @@
+const std = @import("std");
+
+test "fixed" {
+    const x: f32 align(128) = 12.34;
+    std.testing.expect(@ptrToInt(&x) % 128 == 0);
+}