Fix duplicate JIT frames on tail call re-entry

walk_ruby_stack is re-entered via tail calls to process more frames.
On re-entry, in_jit was recomputed from record->state.pc which hasn't
changed (non-FP path), causing the JIT frame to be pushed again on
every tail call. Guard with !jit_detected so the JIT frame is only
pushed once on the first entry.

Author: dalehamel

support/ebpf/ruby_tracer.ebpf.c

@@ -453,7 +453,8 @@ static EBPF_INLINE ErrorCode walk_ruby_stack(
 
   // Detect if the CPU PC is in the JIT region.
   bool in_jit = rubyinfo->jit_start > 0 && record->state.pc >= rubyinfo->jit_start &&
-                record->state.pc < rubyinfo->jit_end;
+                record->state.pc < rubyinfo->jit_end &&
+                !record->rubyUnwindState.jit_detected;
 
   if (in_jit) {
     record->rubyUnwindState.jit_detected = true;