Revert "Revert "util/abuild: Regenerate xcompile on every abuild run""

This reverts commit d94f8bbe9da290e120df20bf244920436e9510e7.

This is a reland of https://review.coreboot.org/57651. The original
change broke parallel abuild runs since the xcompile file was deleted by
every recursive call to abuild. This issue was fixed by rebasing on top
of a change which only regenerates the xcompile on non-recursive calls.

BUG=None
TEST=Parallel abuild run succeeds.

Change-Id: I086ba7b2ae1b8b14459838bd18ce962a84aa306d
Signed-off-by: Reka Norman <rekanorman@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57913
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>

util/abuild/abuild

@@ -798,6 +798,7 @@ PASSED_BOARDS="$(realpath ${TARGET}/passing_boards)"
 export xcompile="${TARGET}/xcompile"
 
 if [ "$recursive" = "false" ]; then
+	rm -f "${xcompile}"
 	$MAKE -C"${ROOT}" obj="$TARGET/temp" objutil="$TARGET/sharedutils" UPDATED_SUBMODULES=1 "${xcompile}" || exit 1
 	rm -f "$FAILED_BOARDS" "$PASSED_BOARDS"
 fi