Revert "Add prebuilt_build_tool to allow genrules to use prebuil..."

Revert submission 1366377-prebuilt_build_tool_make

Reason for revert: breaks build
Reverted Changes:
I20bf062bb:Export prebuilt tools to Make
I4bb526492:Move some prebuilt build tool configs to Soong
I195b68813:Support per-module MakeVars
Ibcb257e7b:Fix dependency loop with flex
I6150f0f39:Switch cc's use of bison and flex to prebuilt_buil...
I6939451b8:Reland "Use genrules to build a consistent awk."
Idee60640f:Add prebuilt_build_tool modules for genrule use
I00893172b:Rename bison to bison_bin
I82c26be1c:Add prebuilt_build_tool to allow genrules to use p...

Change-Id: I6b3acf306d355f3e0463564c9ebe9482fa0f609e