fix(tvix/eval): fix nested assertions b/340

This commit fixes our handling of `throw` within an `assert`
condition.

Fixes: b/340
Change-Id: I40a383639ec266da50a853f16216b1b7868495da
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10318
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

tvix/eval/src/compiler/mod.rs

@@ -836,6 +836,7 @@ impl Compiler<'_> {
         // Compile the assertion condition to leave its value on the stack.
         self.compile(slot, node.condition().unwrap());
         self.emit_force(&node.condition().unwrap());
+        let throw_idx = self.push_op(OpCode::OpJumpIfCatchable(JumpOffset(0)), node);
         let then_idx = self.push_op(OpCode::OpJumpIfFalse(JumpOffset(0)), node);
 
         self.push_op(OpCode::OpPop, node);
@@ -848,6 +849,7 @@ impl Compiler<'_> {
         self.push_op(OpCode::OpAssertFail, &node.condition().unwrap());
 
         self.patch_jump(else_idx);
+        self.patch_jump(throw_idx);
     }
 
     /// Compile conditional expressions using jumping instructions in the VM.