When reading file content with force==true it is tried to read that file
from file system. Only if the read fails the existence of that file can
have changed and exception is thrown anyway. We just need to move the
"asyncRefresh" into the exception handler.
Hotspot from JDTs ResourceCompilationUnit.getContents()

fixes https://github.com/eclipse-platform/eclipse.platform/issues/1442

tested by Bug_303517