codegen.c: stop peephole optimization for headless case statement.
This fixes
MODIFY
mrbgems/mruby-compiler/core/codegen.c
mrbgems/mruby-compiler/core/codegen.c
@@ -2623,7 +2623,7 @@ codegen(codegen_scope *s, node *tree, int val)
else {
pop();
}
- tmp = genjmp2(s, OP_JMPIF, cursp(), pos2, NOVAL);
+ tmp = genjmp2(s, OP_JMPIF, cursp(), pos2, !head);
pos2 = tmp;
n = n->cdr;
}

codegen.c: stop peephole optimization for headless case statement.

This fixes #5815