limit API tests to only common architectures

limit API tests to only common architectures

Forwarded: not-needed
Last-Update: 2019-04-18

On other architectures they are segfaulting due to bugs in QtScript.
The stacktrace is (obtained on ppc64el):
  #0  SLL_PopRange (end=<synthetic pointer>, start=<synthetic pointer>, N=<optimized out>, head=0x3fffb32004e0) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:742
  #1  PopRange (end=<synthetic pointer>, start=<synthetic pointer>, N=<optimized out>, this=0x3fffb32004e0) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2083
  #2  ReleaseToCentralCache (N=192, cl=<optimized out>, this=0x3fffb3200478) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2795
  #3  QTWTF::TCMalloc_ThreadCache::Cleanup (this=0x3fffb3200478) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2745
  #4  0x00003fffb724c6d8 in QTWTF::TCMalloc_ThreadCache::DeleteCache (heap=0x3fffb3200478) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:3069
  #5  0x00003fffb6a48604 in __nptl_deallocate_tsd () at pthread_create.c:157
  #6  0x00003fffb6a489b8 in start_thread (arg=0x3fffb441f160) at pthread_create.c:322
  #7  0x00003fffb745f870 in clone () at ../sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S:104

QBS is going to be ported away from QtScript, but in the mean time disable
API tests on non-common architectures to make the build pass.

Gbp-Pq: Name disable_tests_qtscript.diff