JIT: refine handle blocking logic

Assertion prop uses `O2K_CONST_INT` for handles, even on 64 bit targets. Make
suitable adjustments to the handle propagation blocking logic.

Problem was introduced in dotnet#1593 and exposed by dotnet#1309.

Fixes dotnet#1777

src/coreclr/src/jit/assertionprop.cpp

@@ -2624,13 +2624,6 @@ GenTree* Compiler::optConstantAssertionProp(AssertionDsc* curAssertion,
 
  case O2K_CONST_LONG:
 
-#ifdef _TARGET_64BIT_
- // Don't propagate handles if we need to report relocs.
- if (opts.compReloc && ((curAssertion->op2.u1.iconFlags & GTF_ICON_HDL_MASK) != 0))
- {
- return nullptr;
- }
-#endif
  if (newTree->gtType == TYP_LONG)
  {
  newTree->ChangeOperConst(GT_CNS_NATIVELONG);
@@ -2646,13 +2639,11 @@ GenTree* Compiler::optConstantAssertionProp(AssertionDsc* curAssertion,
 
  case O2K_CONST_INT:
 
-#ifndef _TARGET_64BIT_
  // Don't propagate handles if we need to report relocs.
  if (opts.compReloc && ((curAssertion->op2.u1.iconFlags & GTF_ICON_HDL_MASK) != 0))
  {
  return nullptr;
  }
-#endif
 
  if (curAssertion->op2.u1.iconFlags & GTF_ICON_HDL_MASK)
  {