[mlir][spirv] Change Spirv.GlobalVariableOp builtin -> built_in (#152148)

GlobalVariableOp describes that built_in specifies SPIR-V BuiltIn
decoration associated with the op. The attribute was defined as builtin
in the tablegen (no uderscore). This was causing correct
GlobalVariableOp decorations like: built_in("GlobalInvocationId") to be
saved as a new attribute making it impossible to access the built_in
attribute through getBuiltinAttr.

Author: moscickimilosz

mlir/include/mlir/Dialect/SPIRV/IR/SPIRVStructureOps.td

@@ -451,7 +451,7 @@ def SPIRV_GlobalVariableOp : SPIRV_Op<"GlobalVariable", [InModuleScope, Symbol]>
     OptionalAttr<I32Attr>:$___location,
     OptionalAttr<I32Attr>:$binding,
     OptionalAttr<I32Attr>:$descriptor_set,
-    OptionalAttr<StrAttr>:$builtin,
+    OptionalAttr<StrAttr>:$built_in,
     OptionalAttr<SPIRV_LinkageAttributesAttr>:$linkage_attributes
   );