stage2: fix small memory leak of test_functions when using `zig test`

The way `zig test` works is that it uses a stand-in

var test_functions: []const TestFn = undefined;

during semantic analysis, but then just before codegen, it swaps out the
value with a constant like this:

const test_functions: []const TestFn = .{foo, bar, baz, etc};

Before this commit, the `Module.Variable` associated with the stand-in
value was leaked; now it is properly cleaned up before being replaced.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/Sema.zig b/src/Sema.zig
index 87216348f2..83b81ef174 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -10762,6 +10762,11 @@ fn zirVarExtended(
     }
 
     const new_var = try sema.gpa.create(Module.Var);
+
+    log.debug("created variable {*} owner_decl: {*} ({s})", .{
+        new_var, sema.owner_decl, sema.owner_decl.name,
+    });
+
     new_var.* = .{
         .owner_decl = sema.owner_decl,
         .init = init_val,