[DirectX] Validator fails with Instructions should not read uninitialized value.

[farzonl]

In DML test like NonzeroCoordinatesSingleLevel_256_b16c32_int_4.dat and QLinearConvDp4aCommonKS_3x1_ConvInt_s8s8_InputVec4.dat

Many select instructions have parameters with undef as either the second or third argument causing a bad read.

we see about 38 of these errrors below are all instances with prefix with the number of times seen:

x4: %35 = select i1 %34, i32 %28, i32 undef
x2: %42 = select i1 %41, i32 %25, i32 undef
x4 %48 = select i1 %47, i32 %43, i32 undef
x8: %70 = select i1 %69, i32 %44, i32 undef
x4: %71 = select i1 %70, i32 %45, i32 undef
x6: %79 = select i1 %78, i32 %30, i32 undef
x2: %92 = select i1 %91, i32 %29, i32 undef
x4: %93 = select i1 %92, i32 %29, i32 undef
x1: %1577 = select i1 %1396, i32 undef, i32 %1576
x1: %1571 = select i1 %1393, i32 undef, i32 %1570
x1: %1572 = select i1 %1393, i32 %1569, i32 undef
x1: %1577 = select i1 %1396, i32 undef, i32 %1576

Will be interesting to see if this has something to do with how we legalized freeze: #136043

Maybe freeze emulation was needed after all: 27dca03

[bogner]

The select with the poison seems to be created in the scalarizer pass