[spirv] nuke spirv-opt (#3877)

lots of AGILEism in spirv-opt
theres BETTER alternatives like https://github.com/renderbag/re-spirv (im not gonna bother for now, it probably has shitty build system)
it sucks

the IR already resolves most of the shader code to just constant load/stores
Spirv-opt passes do not seem to make such a big difference
only introduce extra latency
like for example cbuf pass in IR already removes a lot of code, that spirv_opt would otherwise miss due to the fact it doesn't have cbuf information

Signed-off-by: lizzie <lizzie@eden-emu.dev>

Co-authored-by: crueter <crueter@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3877
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: crueter <crueter@eden-emu.dev>

.patch/spirv-tools/0001-netbsd-fix.patch

@@ -1,14 +0,0 @@
-diff --git a/external/CMakeLists.txt b/external/CMakeLists.txt
-index eb4e69e..3155805 100644
---- a/external/CMakeLists.txt
-+++ b/external/CMakeLists.txt
-@@ -72,7 +72,8 @@ if (SPIRV_TOOLS_USE_MIMALLOC)
-   pop_variable(MI_BUILD_TESTS)
- endif()
- 
--if (DEFINED SPIRV-Headers_SOURCE_DIR)
-+# NetBSD doesn't have SPIRV-Headers readily available on system
-+if (DEFINED SPIRV-Headers_SOURCE_DIR AND NOT ${CMAKE_SYSTEM_NAME} STREQUAL "NetBSD")
-   # This allows flexible position of the SPIRV-Headers repo.
-   set(SPIRV_HEADER_DIR ${SPIRV-Headers_SOURCE_DIR})
- else()