[x86] FPU stack needs to be reset after double conversion

The x86 codegen uses the FPU stack for double/float to long conversions. We
need to clear out the FPU stack after done, to prevent an eventual stack
overflow.

Signed-off-by: Udayan Banerji <udayan.banerji@intel.com>

(cherry picked from commit 05d4f7c4a9e0604a247954220363e28cc92c382d)

Change-Id: I2342de4b4efab74cb88471ded8dcc94899768d7c
4 files changed