Some whitespace errors have crept into a few of the .m files in the Java2D metal pipeline in the lanai repo. The fix for JDK-8253206 has added ".m" (along with .cc, .hh, and .mm) to the list of extensions that jcheck checks for whitespace errors. Once I fix up the merge conflicts, that fix will be in the lanai repo, too. Before I do, I need to fix up the existing whitespace errors in those files.

As long as I am here, I'll also fix the one .metal file (MTL shaders). We might some day want to add that to the list of extensions checked by jcheck.