handle equal directive. this fixes c-crashes/crash-12-x64-cannot-set-a-variable-that-has-already-been-used.c

handle error in applyFixup(). this fixes c-crashes/crash-23-x64-value-does-not-fit-in-the-fixup-field.c

x86: report unsupported instructions in encodeInstruction(). this fixes c-crashes/crash-24-x64-not-is16bitmemoperand.c

Add two crash cases

* crash-23-x64-value-does-not-fit-in-the-fixup-field.c
* crash-24-x64-not-is16bitmemoperand.c

Add crash case crash-22-x64-this-is-not-an-immediate.c

Add crash case crash-21-x64-llvm-error-expected-absolute-expression.c

Mark x86_64 crashes as such. Use platform name in crash filenames.

Add test status script.

```
$ ./run-all-overview.sh

== keystone engine crashers ==

  ✘  ./crash-01-empty-tombstone-value-shouldnt-be-inserted-into-map
  ✘  ./crash-02-index-lt-size-failed
  ✘  ./crash-03-invalid-index
  ✘  ./crash-04-readcount-not-equal-to-one
  ✘  ./crash-05-normal-symbols-cannot-be-unnamed
  ✓  ./crash-06-exponent-has-no-digits-in-apfloat-line-126
  ✓  ./crash-07-exponent-has-no-digits-in-apfloat-line-131
  ✓  ./crash-08-invalid-character-in-exponent-absexponent-case
  ✓  ./crash-09-invalid-character-in-exponent-value-case
  ✘  ./crash-10-stringref-cannot-be-built-from-a-null-argument
  ✘  ./crash-11-elfobjectwriter-should-not-have-constructed-this
  ✘  ./crash-12-cannot-set-a-variable-that-has-already-been-used
  ✘  ./crash-13-hexagon-mc-code-emitter-mk-is-not-equal-to-symbolref
  ✘  ./crash-14-invalid-accessor
  ✘  ./crash-15-expected-macro-to-be-defined
  ✓  ./crash-16-expression-value-must-be-representable-in-32-bits
  ✘  ./crash-17-invalid-size
  ✘  ./crash-18-invalid-access
  ✘  ./crash-19-unable-to-encode-mcoperand
  ✘  ./crash-20-segfault-in-llvm-mcassembler-computefragmentsize

** Results: 15 of 20 tests resulted in a crash **

$
```

Run crash cases in deterministic order

Add segfault crash case crash-20-segfault-in-llvm-mcassembler-computefragmentsize.c

Add crash case crash-19-unable-to-encode-mcoperand.c

This breaks suite/regress/x64_nasm_default_rel.py.

Limit value of local labels (fix #82).

arm: propagate error from ARMAsmParser::validateTargetOperandClass(). this fixes crash-16-expression-value-must-be-representable-in-32-bits.c

propagate error from APFloat::convertFromDecimalString(). this fixes crash-06-exponent-has-no-digits-in-apfloat-line-126.c

mips: propagate error from MipsAsmParser::processInstruction() back to ks_asm(). this fixes issue #110