Add Unit Tests for Buffered and Unbuffered Channels

[abhinavarora]

Adding Unit tests

• Simple Test for Buffered Channel
• Simple Test for Unbuffered Channel
• Unbuffered Channel with num_Writers > num_Readers @kavyasrinet Add unit test with less receivers, more senders for unbuffered channel. #8060
• Unbuffered Channel with num_Writers < num_Readers Added more receivers less senders. Receivers should block. #8061 @kavyasrinet
• Test that closing unbuffered channel closes blocked reader and writer threads @abhinavarora Adding unit tests for checking that closing unbuffered channel closes all blocked senders and receivers #8067
• Test that closing buffered channel closes blocked reader and writer threads @abhinavarora Close buffered channel should unblock the blocked senders and receivers #8109
• Add block when channel empty, successfully transfer when there is a send @kavyasrinet
  Add block when channel empty, successfully transfer when there is a send #8063
• Calling destructor any channel should unblock any threads waiting to write or read from the channel @abhinavarora Fix for program crash when destructor is called before channel close with blocked readers/writers #8197
• Check if receive gets a value of zero when channel is closed @kavyasrinet Add test case to return zero on a closed channel #8167
• Add Panic unit test for Buffered Channel @kavyasrinet @abhinavarora Adding panic logic and test case #8171 Fix for program crash when destructor is called before channel close with blocked readers/writers #8197
• Add Panic unit test for unbuffered channel @abhinavarora Fix for program crash when destructor is called before channel close with blocked readers/writers #8197

[wangkuiyi]

Thanks to @abhinavarora, @kavyasrinet, and @chengduoZH for completing this lit of unit tests!