win32: awt_Graphics.cpp sets the clip region too often, reducing performance

Licensee has proposed changes that he would like to see implemented in new
release of JDK/JAE. The two files that would need changes are:

awt_Graphics.h
awt_Graphics.cpp

See source code changes which he use's to demonstrate improved performance.
Please find attached zip files with the following files in them:

GraphTest.java My java test case
GraphTestFrame.java "
GraphTest.html HTML page
update.log data file for test case

awt_Graphics.h my changes to awt_Graphics.h
awt_Graphics.cxx my changes to awt_Graphics.cxx

The test program reads in a fairly large data file with line string
coordinates in it (it takes 15 seconds or so to read in, so don't be
alarmed if it takes a little while). It creates a two dimensional x and
y array of the line strings. On every paint message, it traverses the x
and y coordinates to call drawPolyline. It does this 5 times to make it
take long enough to get a decent timing. It is set up to run as either
an applet or an application. To run as an applet, type in "appletviewer
GraphTest.html". To run as an application, type in "java GraphTest
update.log" from the directory where you put the files.