cl/_testrt/cast: enable run result test

[xgopilot]

Requested by @luoliwoshang

Summary

• Enable the cl/_testrt/cast run result test that was previously skipped
• Now that issue cl/_testrt/cast: error with panic #1538 is fixed by PR fix(cl):same float-to-int cast overflow behavior with go #1544, the cast test runs correctly
• Remove the skip marker (;) from expect.txt to enable the test

Test plan

• Verified the test passes with LLGO_ROOT=/workspace go test -run "TestRunFromTestrt/cast" ./cl/...

Closes #1561

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.01%. Comparing base (475fe56) to head (2753963).
⚠️ Report is 66 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1562   +/-   ##
=======================================
  Coverage   91.01%   91.01%           
=======================================
  Files          45       45           
  Lines       11971    11971           
=======================================
  Hits        10896    10896           
  Misses        899      899           
  Partials      176      176           

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[luoliwoshang]

resome fail because the goroutine output test is nondeterministic #1563

[luoliwoshang]

@xgopilot merge #1564 to ignore unexpect nondeterministic outputtest

[xgopilot]

Merged PR #1564 ✓

Successfully merged changes from PR #1564 into this branch:

• Change: Skip cl/_testgo/goroutine run result test by setting expect.txt to ;
• Reason: Goroutine test output is nondeterministic by design since multiple goroutines run concurrently without enforced execution order
• Commit: 2753963

This PR now includes both:

1. Enable cl/_testrt/cast run result test (original change)
2. Skip cl/_testgo/goroutine run result test (merged from chore: skip nondeterministic goroutine run result test #1564)

[luoliwoshang]

LGTM