Fix AL/AX is not extended to EAX when calling indirectly
Fix AL/AX is not extended to EAX when calling indirectly

AL/AX should be extended to EAX when calling functions. However, the previous code did this only for direct calls, indirect calls were ignored.
New code also avoid redundant code when generating JMP instruction. (i.e. expanding code should be generated with CALL instruction only)

code4game/tinycc,mirror/tinycc,mirror/tinycc,avih/tinycc,mirror/tinycc,mingodad/tinycc,avih/tinycc,mirror/tinycc,code4game/tinycc,avih/tinycc,mingodad/tinycc,code4game/tinycc,mingodad/tinycc,mingodad/tinycc,avih/tinycc