8227170: (.hg)Ignore the JTwork and JTreport directories generated at the root of the repo

Fix the .hgignore file to properly ignore the following: .DS_Store file, .metadata, .recommenders, JTwork and JTreport directories at the root of the repo (in addition to being ignored as sub-directories). src/utils/hsdis/build/ directory

Reviewed-by: erikj
diff --git a/.hgignore b/.hgignore
index 9016749..3e9b17d 100644
--- a/.hgignore
+++ b/.hgignore
@@ -5,12 +5,13 @@
 ^webrev
 ^.src-rev$
 ^.jib/
-\.DS_Store
-\.metadata/
-\.recommenders/
+(^|/)\.DS_Store
+(^|/)\.metadata/
+(^|/)\.recommenders/
 test/nashorn/script/external
 test/nashorn/lib
 NashornProfile.txt
-.*/JTreport/.*
-.*/JTwork/.*
-.*/.git/.*
+(^|/)JTreport/
+(^|/)JTwork/
+(^|/)\.git/
+^src/utils/hsdis/build/
\ No newline at end of file