mesa: fix memory leak when using shader cache

Fixes: 656ccf4ef8 ("mesa: shader dump/read support for ARB programs")
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30302>

src/mesa/main/arbprogram.c

@@ -402,6 +402,9 @@ set_program_string(struct gl_program *prog, GLenum target, GLenum format, GLsize
    }
    else {
       _mesa_error(ctx, GL_INVALID_ENUM, "glProgramStringARB(target)");
+#ifdef ENABLE_SHADER_CACHE
+      free(replacement);
+#endif
       return;
    }
 
@@ -460,6 +463,9 @@ set_program_string(struct gl_program *prog, GLenum target, GLenum format, GLsize
       }
       ralloc_free(filename);
    }
+#ifdef ENABLE_SHADER_CACHE
+   free(replacement);
+#endif
 }
 
 void GLAPIENTRY