[LNT][Xcode] Add !# header to shim scripts

Add !# header to shim scripts that used for xcode based LNT tests so
shells can correctly identify how to run them.

Author: cachemeifyoucan

cmake/caches/util/xcode_sdk.cmake

@@ -28,6 +28,7 @@ if (CMAKE_C_COMPILER)
   macro(create_shim VARIABLE TOOLNAME)
     xcrun_find(SDK_TOOL_BIN ${TOOLNAME})
     file(WRITE ${CMAKE_BINARY_DIR}/${TOOLNAME} "
+#!/bin/bash
 # Shim to have the tool use the correct libLTO.dylib
 DYLD_LIBRARY_PATH=\"${COMPILER_DIR}/../lib:$DYLD_LIBRARY_PATH\" ${SDK_TOOL_BIN} \"$@\"
     ")