Enable global constant propagation for GT_LCL_FLD (#61209)

These are leaf nodes without side effects, and we can
sometimes evaluate them in VN, so it does not seem like
there is any reason not to enable propagation for them.

src/coreclr/jit/assertionprop.cpp

@@ -5605,8 +5605,9 @@ Compiler::fgWalkResult Compiler::optVNConstantPropCurStmt(BasicBlock* block, Sta
             break;
 
         case GT_LCL_VAR:
+        case GT_LCL_FLD:
             // Make sure the local variable is an R-value.
-            if ((tree->gtFlags & (GTF_VAR_DEF | GTF_DONT_CSE)))
+            if ((tree->gtFlags & (GTF_VAR_USEASG | GTF_VAR_DEF | GTF_DONT_CSE)) != GTF_EMPTY)
             {
                 return WALK_CONTINUE;
             }