Move glslc to cas to enable remote execution (#155832)

Meta:
`fbsource//xplat/caffe2:gen_torch_vulkan_spv_cpp` takes on average 2 min to build and is one of topmost slow targets in fbandroid.
See: https://fb.workplace.com/groups/2840058936242210/posts/4067730240141734

This target hat to run locally because it uses manifold backend for dotslash. This diff moves the `glslc` to cas backend so that it can run on RE.

Here are commands executed:
```
% manifold get dotslash_glslc/flat/glslc-linux-x86_64.tar.gz
% manifold get dotslash_glslc/flat/glslc-macos-v2024_4.tar.gz
% manifold get dotslash_glslc/flat/glslc-windows-v2024_3.tar

% ls
-rw-r--r--  1 navidq  staff   2.0M Jun 12 10:02 glslc-linux-x86_64.tar.gz
-rw-r--r--  1 navidq  staff   4.7M Jun 12 10:03 glslc-macos-v2024_4.tar.gz
-rw-r--r--  1 navidq  staff   4.4M Jun 12 10:03 glslc-windows-v2024_3.tar

% frecli --use-case dotslash cas upload-blob --skip-find-missing glslc-linux-x86_64.tar.gz
ea5d674e0e7e9782be3f5c309e3484732e5b3a331cbe3258f3e929002811627b:2072937

% frecli --use-case dotslash cas upload-blob --skip-find-missing glslc-macos-v2024_4.tar.gz
1331dc691835e4676832b7c21ef669083a3acc8856981583d0698192f466c51a:4898649

% frecli --use-case dotslash cas upload-blob --skip-find-missing glslc-windows-v2024_3.tar
76181fbb1ce5c62d0c905db26df3a64e999d0baff2e93270775921daa91e3a1a:4585984
```

Differential Revision: [D76513735](https://our.internmc.facebook.com/intern/diff/D76513735/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/155832
Approved by: https://github.com/GregoryComer

buckbuild.bzl

@@ -738,7 +738,6 @@ def vulkan_spv_shader_library(name, spv_filegroup):
         },
         cmd = " ".join(genrule_cmd),
         default_outs = ["."],
-        labels = ["uses_dotslash"],
     )
 
     fb_xplat_cxx_library(