Fix an embarrasing error in m68k which fixes 60 tests.

m68k/cgcpu.pas, tcg68k.g_flags2reg:
  * don't sign extend the flag value which was stored to the register, but instead do a "AND 1" on it to reduce it to 1 bit; afterall Booleans in Pascal are either 0 or 1 and not 0 or $FF

+ added test


git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@25598 3ad0048d-3df7-0310-abae-a5850022a9f2