[Vulkan] Remove GLSL Code Gen (#91912)

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GLSL Code Gen is not used, so this diff removes
- GLSL parts of ShaderSource
- Anything enclosed by USE_VULKAN_SHADERC_RUNTIME, as well as the flag itself
- gen_vulkan_glsl script

Plus some additional refactoring

Differential Revision: [D41358861](https://our.internmc.facebook.com/intern/diff/D41358861/)

**NOTE FOR REVIEWERS**: This PR has internal Meta-specific changes or comments, please review them on [Phabricator](https://our.internmc.facebook.com/intern/diff/D41358861/)!
Pull Request resolved: https://github.com/pytorch/pytorch/pull/91912
Approved by: https://github.com/mcr229
diff --git a/tools/BUCK.bzl b/tools/BUCK.bzl
index 58a49fd..3d685f4 100644
--- a/tools/BUCK.bzl
+++ b/tools/BUCK.bzl
@@ -211,18 +211,6 @@
         srcs = [
             "gen_vulkan_spv.py",
         ],
-        base_module = "",
-        deps = [
-            torchgen_deps,
-            ":gen_aten_vulkan_glsl_lib",
-        ],
-    )
-
-    python_library(
-        name = "gen_aten_vulkan_glsl_lib",
-        srcs = [
-            "gen_vulkan_glsl.py",
-        ],
         base_module = "tools",
         deps = [
             torchgen_deps,
@@ -231,12 +219,11 @@
 
     python_binary(
         name = "gen_aten_vulkan_spv_bin",
-        main_module = "gen_vulkan_spv",
+        main_module = "tools.gen_vulkan_spv",
         visibility = [
             "PUBLIC",
         ],
         deps = [
-            ":gen_aten_vulkan_glsl_lib",
             ":gen_aten_vulkan_spv_lib",
         ],
     )
@@ -249,7 +236,6 @@
         contacts = contacts,
         visibility = ["PUBLIC"],
         deps = [
-            ":gen_aten_vulkan_glsl_lib",
             ":gen_aten_vulkan_spv_lib",
         ],
     )