Merge 'Implement Noop bytecode' from Pedro Muniz

This PR implements Noop. I really don't know what else to say. This
bytecode according to sqlite does: _Do nothing. Continue downward to the
next opcode._ I advanced the program counter to account for continuing
to the next instruction.

Closes #795

COMPAT.md

@@ -487,7 +487,7 @@ Modifiers:
 | Next           | No     |         |
 | NextAsync      | Yes    |         |
 | NextAwait      | Yes    |         |
-| Noop           | No     |         |
+| Noop           | Yes     |         |
 | Not            | Yes    |         |
 | NotExists      | Yes    |         |
 | NotFound       | No     |         |

core/vdbe/explain.rs

@@ -1154,6 +1154,15 @@ pub fn insn_to_str(
                 0,
                 format!("r[{}]=(r[{}] || r[{}])", dest, lhs, rhs),
             ),
+            Insn::Noop => (
+                "Noop",
+                0,
+                0,
+                0,
+                OwnedValue::build_text(Rc::new("".to_string())),
+                0,
+                String::new(),
+            ),
         };
     format!(
         "{:<4}  {:<17}  {:<4}  {:<4}  {:<4}  {:<13}  {:<2}  {}",

core/vdbe/insn.rs

@@ -569,6 +569,7 @@ pub enum Insn {
         rhs: usize,
         dest: usize,
     },
+    Noop,
 }
 
 fn cast_text_to_numerical(value: &str) -> OwnedValue {

core/vdbe/mod.rs

@@ -2457,6 +2457,11 @@ impl Program {
                         exec_or(&state.registers[*lhs], &state.registers[*rhs]);
                     state.pc += 1;
                 }
+                Insn::Noop => {
+                    // Do nothing
+                    // Advance the program counter for the next opcode
+                    state.pc += 1
+                }
             }
         }
     }