Update recursion-limit.swift

Use the `%diff` substitution to ensure that `--strip-trailing-cr` is used as appropriate to ignore line endings.  This should repair the Windows builders.

Author: compnerd

test/Demangle/recursion-limit.swift

@@ -1,10 +1,10 @@
 ; This is not really a Swift source file: -*- Text -*-
 
 RUN: swift-demangle < %S/Inputs/bigtype.txt 2>&1 > %t.check
-RUN: diff -u %S/Inputs/bigtype-demangle.txt %t.check
+RUN: %diff -u %S/Inputs/bigtype-demangle.txt %t.check
 
 RUN: swift-demangle -remangle-new < %S/Inputs/bigtype.txt > %t.check 2>&1 || true
-RUN: diff -u %S/Inputs/bigtype-remangle.txt %t.check
+RUN: %diff -u %S/Inputs/bigtype-remangle.txt %t.check
 
 RUN: swift-demangle -remangle-objc-rt < %S/Inputs/bigtype.txt > %t.check 2>&1 || true
-RUN: diff -u %S/Inputs/bigtype-objcrt.txt %t.check
+RUN: %diff -u %S/Inputs/bigtype-objcrt.txt %t.check