tests/tcg: new test for i386 FPREM and FPREM1

tests/tcg: new test for i386 FPREM and FPREM1

This is setting the stage for a cleanup of FPREM and FPREM1 helpers while being
sure that they behave same as bare metal.

The test constructs operands using combinations of corner cases for the
floating-point bitfields and prints operands, result and FPU status word for
FPREM and FPREM1. The outputs can then be compared between bare metal and QEMU.
The 'run-test-i386-fprem' make target does just that.

Signed-off-by: Catalin Patulea <catalinp@google.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>