treewide: remove unnecessary cache.h inclusion

treewide: remove unnecessary cache.h inclusion

Several files were including cache.h solely to get other headers, such
as trace.h and trace2.h.  Since the last few commits have modified
files to make these dependencies more explicit, the inclusion of cache.h
is no longer needed in several cases.  Remove it.

Signed-off-by: Elijah Newren <newren@gmail.com>
Acked-by: Calvin Wan <calvinwan@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>