Fix 32-bit non-SIMD FP regression tests - Introduce a new FLOATTEST value ("387") on Un*x systems that will compare the floating point DCT/IDCT algorithms against the expected results from the C algorithms when built using 32-bit code and -mfpmath=387. - Extend the Windows regression tests so that they work properly when building libjpeg-turbo with 32-bit code and without SIMD, using either Visual C++ (tested with 2008, 2010, 2015) or MinGW.