[CI] add assert-enabled MLIR option (#78)

This deprecates the use of release-build LLVM hosted by the LLVM project, which makes debugging harder for developers.

This PR implements the following solution:
1. Create LLVM release tarballs with assert enabled on our own (using Docker)
2. Host them in our own GitHub repositories
3. Use our LLVM for CI and/or development if `TRITON_USE_ASSERT_ENABLED_LLVM=1` is set.

include/triton/Dialect/Triton/IR/TritonDialect.td

@@ -23,7 +23,8 @@ def Triton_Dialect : Dialect {
   let dependentDialects = [
     "arith::ArithmeticDialect",
     "StandardOpsDialect",
-    "scf::SCFDialect"
+    "scf::SCFDialect",
+    "gpu::GPUDialect",
 
     // Since LLVM 15
     // "cf::ControlFlowDialect",