binman: Collect bintools for images when replacing entries

Binman entries can use other executables to compute their data, usually
in their ObtainContents() methods. Subclasses of Entry_section would use
bintools in their BuildSectionData() method instead, which is called
from several places including their Pack().

These binary tools are resolved correctly while building an image from a
device-tree description so that they can be used from these methods.
However, this is not being done when replacing entries in an image,
which can result in an error as the Pack() methods attempt to use them.

Collect and resolve entries' bintools also when replacing entries to fix
Pack() errors. Add a way to mock bintool usage in the testing entry type
and tests that check bintools are being resolved for such an entry.

Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/control.py b/tools/binman/control.py
index d4c8dc8..e170aea 100644
--- a/tools/binman/control.py
+++ b/tools/binman/control.py
@@ -299,6 +299,7 @@
     """
     state.PrepareFromLoadedData(image)
     image.LoadData()
+    image.CollectBintools()
 
     # If repacking, drop the old offset/size values except for the original
     # ones, so we are only left with the constraints.