gprofng: fix a memory leak in the mxv-pthreads example

gprofng: fix a memory leak in the mxv-pthreads example

Fix a bug where the main program does not free the rows of
the matrix. The memory for thread_data_arguments is also
not released. In function check_results, the memory for the
marker vector is not released.
The usage of the verbose veriable has been extended to
print more messages.

gprofng/ChangeLog
2024-10-16  Ruud van der Pas  <ruud.vanderpas@oracle.com>

	PR 32273
	PR 32274
	* mxv-pthreads/src/main.c: add calls to free() to
	release the memory allocated for array A and vector
	marker. Improve the usage of the verbose variable.
	* mxv-pthreads/src/manage_data.c: add a diagnostic
	printf statement.
	* mxv-pthreads/src/mydefs.h: adapt prototype to
	match the changes in main.c.