[NFC] fix trivial typos in documents and comments

"is is" -> "is", "if if" -> "if", "or or" -> "or"

llvm-svn: 329878
diff --git a/llvm/docs/ExceptionHandling.rst b/llvm/docs/ExceptionHandling.rst
index e65c1be..18ff53c 100644
--- a/llvm/docs/ExceptionHandling.rst
+++ b/llvm/docs/ExceptionHandling.rst
@@ -365,7 +365,7 @@
 
 When used in the native Windows C++ exception handling implementation, this
 intrinsic serves as a placeholder to delimit code before a catch handler is
-outlined.  When the handler is is outlined, this intrinsic will be replaced
+outlined.  When the handler is outlined, this intrinsic will be replaced
 by instructions that retrieve the exception object pointer from the frame
 allocation block.