Returns the approximate accumlated elapsed time (in milliseconds)
spent in compilation.
If multiple threads are used for compilation, this value is
summation of the approximate time that each thread spent in compilation.
This method is optionally supported by the platform.
A Java virtual machine implementation may not support the compilation
time monitoring. The {@link #isCompilationTimeMonitoringSupported}
method can be used to determine if the Java virtual machine
supports this operation.
This value does not indicate the level of performance of
the Java virtual machine and is not intended for performance comparisons
of different virtual machine implementations.
The implementations may have different definitions and different
measurements of the compilation time.
