SPIRV: Set NoPHIs property after selection

There should be no PHIs after selection, as OpPhi is used
instead. This hopefully avoids errors in #135277.

Author: arsenm

llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp

@@ -269,6 +269,12 @@ class SPIRVInstructionSelect : public InstructionSelect {
     return InstructionSelect::getRequiredProperties().reset(
         MachineFunctionProperties::Property::RegBankSelected);
   }
+
+  MachineFunctionProperties getClearedProperties() const override {
+    // No generic Phis remain, replaced with OpPhi
+    return InstructionSelect::getClearedProperties().reset(
+        MachineFunctionProperties::Property::NoPHIs);
+  }
 };
 } // namespace