Pattern fixes

backends/write_firrtl/write_firrtl_shiftx.pat

-_shiftx____top_shiftx_v_21_107 <= dshr(lut, a)
+  _shiftx____top_shiftx_v_0_107 <= dshr(lut, validif(not(bits(a, 4, 4)), a))

backends/write_json/json_o_aig.pat

-          "model": "$add:0:0:1:1:1",
+"model": "$add:1U:1U:1",
\ No newline at end of file

backends/write_json/write_json_aig.pat

-          "model": "$add:0:0:1:1:1",
+"model": "$add:1U:1U:1",
\ No newline at end of file

backends/write_smv/write_smv_shiftx.pat

-    _$shiftx$###top_shiftx#v#21$107_Y := resize(resize(0ub32_10100000100010100010100010101100, 63) >> _a\[4:0\], 1);
+    _$shiftx$###top_shiftx#v#0$107_Y := bool(_a[4:4]) ? resize(resize(0ub32_10100000100010100010100010101100, 63) << _0[4:0], 1) : resize(resize(0ub32_10100000100010100010100010101100, 63) >> _a[4:0], 1);
+    _y := _$shiftx$###top_shiftx#v#0$107_Y;