Revert "Ninja: job pool support for compiling and linking"

This reverts commit 529b58d1c6221fb52ab1fb3b18ba176dd4af9c0f.
Merge topic 'ninja-compile-link-pool' into next

ac363b5 Revert "Ninja: job pool support for compiling and linking"
Ninja: job pool support for compiling and linking

Could be tested by setting the environment
variable NINJA_STATUS=[%r]
Merge topic 'ninja-compile-link-pool' into next

5561d55 Ninja: job pool support for compiling and linking