Vulkan: Avoid linking to SPIR-V validation if possible We unconditionally link to $angle_spirv_tools_dir:spvtools_val, but we only use SPIR-V validation with ASSERTs. This CL removes this dependency when ASSERTs are disabled. Bug: angleproject:4887 Test: CQ Change-Id: Ic403b78196ecd895e4a0cdefb54ab4497651ccac Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2375872 Commit-Queue: Tim Van Patten <timvp@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com>