+ i386: generate optimized code for 64-bit arithmetic shifts by constant amount. Shifts by 63 and by less than 32 take just two instructions, shifts by 32..62 bits are done with 3 instructions.

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@25880 3ad0048d-3df7-0310-abae-a5850022a9f2