[ABI] Improvements to avoid UB and warnings, clean build with MSAN

* Added more clang compilers on CI (CI)
  * Added memory sanitizer to build matrix (CI)
  * Use problem matcher in all builds (CI)
  * Fixed the use of some constructs in tests
  * Fixed warnings about unused functions in tests
  * Fixed warnings about unused variables caused by some build options
  * Fixed tests to be clean with MSAN (zeroing memory filled by JIT code)
  * Removed -Wclass-memaccess (gcc) from ignored warnings
  * Removed -Wconstant-logical-operand (clang) from ignored warnings
  * Removed -Wunnamed-type-template-args (clang) from ignored warnings
  * Reworked InstData and InstExData to not cause UB (ABI break)

Unfortunately the existing InstData and InstExData was not good for static
analysis and in general compilers emitted warnings regarding accessing
InstNode::_opArray. The reason was that InstExNode added one or two
more operands which extended InstData::_opArray, but there was no way to
tell the C++ compiler about this layout.

It has been changed to InstNode having no operands and InstNodeWithOperands
being templatized for the right number of operands. Nodes that need to
inherit InstNode would just inherit InstNodeWithOperands<N>. It works the
same way as before, just the class hierarchy changed a little.

test/asmjit_test_instinfo.cpp

@@ -13,6 +13,9 @@
 
 using namespace asmjit;
 
+namespace {
+
+#if !defined(ASMJIT_NO_X86)
 static char accessLetter(bool r, bool w) noexcept {
   return r && w ? 'X' : r ? 'R' : w ? 'W' : '_';
 }
@@ -140,6 +143,7 @@ static void printInfoExtra(Arch arch, InstId instId, InstOptions options, const
   Operand_ opArray[] = { std::forward<Args>(args)... };
   printInfo(arch, inst, opArray, sizeof...(args));
 }
+#endif // !ASMJIT_NO_X86
 
 static void testX86Arch() {
 #if !defined(ASMJIT_NO_X86)
@@ -165,9 +169,11 @@ static void testX86Arch() {
 
   printInfoExtra(arch, Inst::kIdVaddpd, InstOptions::kNone, k1, zmm0, zmm1, zmm2);
   printInfoExtra(arch, Inst::kIdVaddpd, InstOptions::kX86_ZMask, k1, zmm0, zmm1, zmm2);
-#endif
+#endif // !ASMJIT_NO_X86
 }
 
+} // {anonymous}
+
 int main() {
   printf("AsmJit Instruction Info Test-Suite v%u.%u.%u\n",
     unsigned((ASMJIT_LIBRARY_VERSION >> 16)       ),