std.debug.assert: remove special case for test builds

Previously, std.debug.assert would `@panic` in test builds,
if the assertion failed. Now, it's always `unreachable`.

This makes release mode test builds more accurately test
the actual code that will be run.

However this requires tests to call `std.testing.expect`
rather than `std.debug.assert` to make sure output is correct.

Here is the explanation of when to use either one, copied from
the assert doc comments:

Inside a test block, it is best to use the `std.testing` module
rather than assert, because assert may not detect a test failure
in ReleaseFast and ReleaseSafe mode. Outside of a test block, assert
is the correct function to use.

closes #1304

1 files changed, 2 insertions, 2 deletions

diff --git a/src-self-hosted/test.zig b/src-self-hosted/test.zig
index de551cf7f7..4be6d53932 100644
--- a/src-self-hosted/test.zig
+++ b/src-self-hosted/test.zig
@@ -4,7 +4,7 @@ const builtin = @import("builtin");
 const Target = @import("target.zig").Target;
 const Compilation = @import("compilation.zig").Compilation;
 const introspect = @import("introspect.zig");
-const assertOrPanic = std.debug.assertOrPanic;
+const testing = std.testing;
 const errmsg = @import("errmsg.zig");
 const ZigCompiler = @import("compilation.zig").ZigCompiler;
 
@@ -210,7 +210,7 @@ pub const TestContext = struct {
                 @panic("build incorrectly failed");
             },
             Compilation.Event.Fail => |msgs| {
-                assertOrPanic(msgs.len != 0);
+                testing.expect(msgs.len != 0);
                 for (msgs) |msg| {
                     if (mem.endsWith(u8, msg.realpath, path) and mem.eql(u8, msg.text, text)) {
                         const span = msg.getSpan();