Revert "MDL-33774 get rid of cache in global var"

This reverts commit b48bb8c9112e818ad2c379ce4a54f254287c9ec3.
TEMP debugging of usage format_xxx without context
Revert "TEMP debugging of usage format_xxx without context"

This reverts commit f64eb3d04e9e1dcaf20b7eec9f207bb72fc34c41.
MDL-37979 missing context in format_x()
Revert "MDL-37979 missing context in format_x()"

This reverts commit 5dfdc49163691110039294d90c923f7892d35b1f.
Adding contexts to questions
Revert "Adding contexts to questions"

This reverts commit 4ea530235c56ac87c34153906d97c430f4caa865.
Reset filters caches between unit tests