Support phony_output as a BuildParam Arg in RuleBuilder

This allows a build rule to set the phony_output argument to ninja.
It's used to get ninja to ignore output files similar to .PHONY for
make.
It will cause the build rule to be run every time regardless of if or
when the output file was created.

Test: m android.hardware.bluetooth.audio-update-api &&
      git restore bluetooth/audio/aidl/aidl_api/* &&
      m android.hardware.bluetooth.audio-update-api
Bug: 353287999

Change-Id: I47b0b9e3ce2d8cb637b0102031193c81de24a680