test: remove standalone issue_13970 test

It's been disabled for ages and has bitrotted. Someone can readd it later if
they feel like it actually adds value.

test/standalone/build.zig.zon

@@ -15,10 +15,6 @@
         .test_runner_module_imports = .{
             .path = "test_runner_module_imports",
         },
-        // https://github.com/ziglang/zig/issues/17483
-        //.issue_13970 = .{
-        //    .path = "issue_13970",
-        //},
         .shared_library = .{
             .path = "shared_library",
         },

test/standalone/issue_13970/build.zig

@@ -1,32 +0,0 @@
-const std = @import("std");
-
-pub fn build(b: *std.Build) void {
-    const test_step = b.step("test", "Test it");
-    b.default_step = test_step;
-
-    const test1 = b.addTest(.{
-        .root_module = b.createModule(.{
-            .root_source_file = b.path("test_root/empty.zig"),
-            .target = b.graph.host,
-        }),
-        .test_runner = "src/main.zig",
-    });
-    const test2 = b.addTest(.{
-        .root_module = b.createModule(.{
-            .root_source_file = b.path("src/empty.zig"),
-            .target = b.graph.host,
-        }),
-        .test_runner = "src/main.zig",
-    });
-    const test3 = b.addTest(.{
-        .root_module = b.createModule(.{
-            .root_source_file = b.path("empty.zig"),
-            .target = b.graph.host,
-        }),
-        .test_runner = "src/main.zig",
-    });
-
-    test_step.dependOn(&b.addRunArtifact(test1).step);
-    test_step.dependOn(&b.addRunArtifact(test2).step);
-    test_step.dependOn(&b.addRunArtifact(test3).step);
-}

test/standalone/issue_13970/src/main.zig

@@ -1,8 +0,0 @@
-const std = @import("std");
-const package = @import("package.zig");
-const root = @import("root");
-const builtin = @import("builtin");
-
-pub fn main() !void {
-    _ = package.decl;
-}

test/standalone/issue_13970/src/package.zig

@@ -1 +0,0 @@
-pub const decl = 0;