[Java 21] Fix runtime get hang due to invalid Strand states

[warunalakshitha]

Purpose

$Subject

Check List

• Read the Contributing Guide
• Updated Change Log
• Checked Tooling Support (#)
• Added necessary tests
  • Unit Tests
  • Spec Conformance Tests
  • Integration Tests
  • Ballerina By Example Tests
• Increased Test Coverage
• Added necessary documentation
  • API documentation
  • Module documentation in Module.md files
  • Ballerina By Examples

[codecov]

Codecov Report

Attention: Patch coverage is 86.36364% with 6 lines in your changes missing coverage. Please review.

Project coverage is 75.01%. Comparing base (fea2118) to head (6860ffb).
Report is 10 commits behind head on java21.

Files with missing lines	Patch %	Lines
.../ballerina/runtime/internal/scheduling/Strand.java	75.00%	0 Missing and 3 partials ⚠️
.../java/org/ballerinalang/langlib/runtime/Sleep.java	66.66%	2 Missing ⚠️
...rinalang/debugadapter/runtime/DebuggerRuntime.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             java21   #43434   +/-   ##
=========================================
  Coverage     75.00%   75.01%           
+ Complexity    56729    56725    -4     
=========================================
  Files          3447     3447           
  Lines        218874   218878    +4     
  Branches      28846    28846           
=========================================
+ Hits         164177   164187   +10     
+ Misses        45743    45736    -7     
- Partials       8954     8955    +1     

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