Update test_compile.cpp (#1812)

* Update test_compile.cpp

Prevent the error:
"variable 'temp' is uninitialized when used here"

Since one of the generated kernels starts with:

__kernel void sample_test(__global float *src, __global int *dst)
{
    float temp;
    int  tid = get_global_id(0);
    dst[tid] = dst[tid] + temp;

* Update test_compile.cpp

clang format

* Update test_compile.cpp

Change the "0.0" literal to "0.0f" for devices that don't support FP64.