[mlir][tblgen] Fully qualify more names.

[csigg]

Summary

Fixes compilation issues when the generated code does not live in the mlir namespace.

[mehdi_amini]

I thought I fixed most of these in the last few days already?

Feel free to land what hasn't!

mlir/tools/mlir-tblgen/OpDefinitionsGen.cpp

 static const char *const readBytecodeSegmentSize = R"(
 if ($_reader.getBytecodeVersion() < /*kNativePropertiesODSSegmentSize=*/6) {
   ::mlir::DenseI32ArrayAttr attr;
   if (::mlir::failed($_reader.readAttribute(attr))) return ::mlir::failure();
   if (attr.size() > static_cast<int64_t>(sizeof($_storage) / sizeof(int32_t))) {
     $_reader.emitError("size mismatch for operand/result_segment_size");
     return ::mlir::failure();
   }
-  llvm::copy(::llvm::ArrayRef<int32_t>(attr), $_storage.begin());
+  ::llvm::copy(::llvm::ArrayRef<int32_t>(attr), $_storage.begin());
 } else {
   return $_reader.readSparseArray(::llvm::MutableArrayRef($_storage));
 }
 )";
 
 /// Write operand/result segment_size to bytecode.
 static const char *const writeBytecodeSegmentSize = R"(
 if ($_writer.getBytecodeVersion() < /*kNativePropertiesODSSegmentSize=*/6)

mlir/tools/mlir-tblgen/OpFormatGen.cpp

if (!allResultTypes &&
     auto interleaveFn = [&](const NamedTypeConstraint &result) {
       // If the result is variadic emit the parsed size.
       if (result.isVariableLength())
         body << "static_cast<int32_t>(" << result.name << "Types.size())";
       else
         body << "1";
     };
     if (op.getDialect().usePropertiesForAttributes()) {
-      body << "llvm::copy(ArrayRef<int32_t>({";
+      body << "::llvm::copy(::llvm::ArrayRef<int32_t>({";
       llvm::interleaveComma(op.getResults(), body, interleaveFn);
       body << formatv("}), "
                       "result.getOrAddProperties<{0}::Properties>()."
                       "resultSegmentSizes.begin());\n",
                       op.getCppClassName());
     } else {
       body << "  result.addAttribute(\"resultSegmentSizes\", "
            << "parser.getBuilder().getDenseI32ArrayAttr({";