[infra] Cleanup permissions in our docker build tasks

Swarming appears to have changed recently to fail loudly
if it cannot delete any files. This can happen for
our docker outputs (e.g. the /OUT/obj folder).

I am hopeful that in a Bazel world, we won't have
issues like this because of Bazel's ability to keep
things more hermetic.

Change-Id: I21d9138bc25b42794006322e1b8987787222d5da
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/436816
Reviewed-by: Eric Boren <borenet@google.com>

infra/bots/recipe_modules/build/resources/docker-compile.sh

@@ -18,3 +18,5 @@ cd /SRC/skia
 ./bin/fetch-gn
 ./bin/gn gen /OUT "--args=$1"
 ninja -C /OUT
+
+chmod -R 0777 /OUT/*

infra/canvaskit/build_canvaskit.sh

@@ -25,3 +25,4 @@ CANVASKIT_DIR=$BASE_DIR/../../modules/canvaskit
 
 BUILD_DIR=/OUT $CANVASKIT_DIR/compile.sh $@
 
+chmod -R 0777 /OUT/*

infra/canvaskit/build_gmtests.sh

@@ -22,5 +22,5 @@ CANVASKIT_DIR=$BASE_DIR/../../modules/canvaskit
 BUILD_DIR=/OUT $CANVASKIT_DIR/compile_gm.sh $@
 
 # Make sure everybody can read and write the contents of /OUT
-chmod -R a+rw /OUT/*
+chmod -R 0777 /OUT/*
 

infra/pathkit/build_pathkit.sh

@@ -25,3 +25,4 @@ PATHKIT_DIR=$BASE_DIR/../../modules/pathkit
 
 BUILD_DIR=/OUT $PATHKIT_DIR/compile.sh $@
 
+chmod -R 0777 /OUT/*