glsl/tests: fix memory leaks

Fixes: 09cc5f0c37 - glsl: use pipe_screen::nir_options instead of NirOptions

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36539>

src/compiler/glsl/tests/builtin_variable_test.cpp

@@ -79,6 +79,7 @@ common_builtin::SetUp()
 void
 common_builtin::TearDown()
 {
+   free(this->ctx.screen);
    ralloc_free(this->mem_ctx);
    this->mem_ctx = NULL;
 

src/compiler/glsl/tests/test_gl_lower_mediump.cpp

@@ -216,6 +216,7 @@ namespace
 
       /* Store the source for printing from later assertions. */
       this->source = source;
+      free(local_ctx.screen);
    }
 
    // A predicate-formatter for asserting that two integers are mutually prime.