Fix and extend *FCAST test in tcctest.c
Fix and extend *FCAST test in tcctest.c

Result of float to unsigned integer conversion is undefined if float is
negative. This commit take the absolute value of the float before doing
the conversion to unsigned integer and add more float to integer
conversion test.

avih/tinycc,run4flat/tinycc,metaeducation/tcc,code4game/tinycc,andrewchambers/tccmirror,leeduhem/tinycc,seyko2/tinycc,gfwilliams/tinycc,run4flat/tinycc,avih/tinycc,rchandramouli/tinycc,fstudio/tinycc,mirror/tinycc,mirror/tinycc,mingodad/tinycc,seyko2/tinycc,run4flat/tinycc,leeduhem/tinycc,seyko2/tinycc,andrewchambers/tccmirror,fstudio/tinycc,mingodad/tinycc,fstudio/tinycc,gfwilliams/tinycc,leeduhem/tinycc,andrewchambers/tccmirror,andreiw/tinycc,mingodad/tinycc,leeduhem/tinycc,rchandramouli/tinycc,run4flat/tinycc,rchandramouli/tinycc,andrewchambers/tccmirror,metaeducation/tcc,seyko2/tinycc,avih/tinycc,mirror/tinycc,mingodad/tinycc,code4game/tinycc,andrewchambers/tccmirror,seyko2/tinycc,andreiw/tinycc,fstudio/tinycc,gfwilliams/tinycc,fstudio/tinycc,mirror/tinycc,alfonsokim/tinycc,metaeducation/tcc,avih/tinycc,gfwilliams/tinycc,leeduhem/tinycc,run4flat/tinycc,andreiw/tinycc,alfonsokim/tinycc,metaeducation/tcc,metaeducation/tcc,rchandramouli/tinycc,code4game/tinycc,alfonsokim/tinycc,alfonsokim/tinycc,gfwilliams/tinycc,alfonsokim/tinycc,rchandramouli/tinycc