testing/cc65: disable tests

currently failing on package builders

gcc -O2 -Wall -W -Wextra -funsigned-char -fwrapv -fno-strict-overflow -o ../../testwrk/ref/array.host array.c
array.c:16:1: error: return type defaults to 'int' [-Wimplicit-int]
   16 | main() {
      | ^~~~
array.c:36:1: error: return type defaults to 'int' [-Wimplicit-int]
   36 | f() {
      | ^
array.c:49:1: error: return type defaults to 'int' [-Wimplicit-int]
   49 | g(x, y)
      | ^
array.c: In function 'f':
array.c:47:1: warning: control reaches end of non-void function [-Wreturn-type]
   47 | }
      | ^
array.c: In function 'g':
array.c:62:1: warning: control reaches end of non-void function [-Wreturn-type]
   62 | }
      | ^
make[1]: *** [Makefile:57: ../../testwrk/ref/array.ref] Error 1
make: *** [Makefile:27: continue] Error 2
>>> ERROR: cc65: check failed