Test external tools separately, without running `rizin` first

[XVilka]

It will reduce tests running time. For example:

NAME=rz-asm arm asm/dis endian
FILE=-
CMDS=<<EOF
!rz-asm -a arm -b32 "mov r0, 3"
!rz-asm -a arm -b32 -e "mov r0, 3"
!rz-asm -a arm -b32 -d 0300a0e3
!rz-asm -a arm -b32 -e -d e3a00003
EOF
EXPECT=<<EOF
0300a0e3
e3a00003
mov r0, 3
mov r0, 3
EOF
RUN

Here rz-test runs 1) rizin first 2) runs rz-asm every time separately. Likely, the need to run rizin for these kind of test can be gone.

[XVilka]

What we could do - have a "shebang" string on top of the every test file, so that it would tell what binary to use to run the test.