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

This reverts commit 2c72c02b0a28684f6fc458b357d971465a1c8ed1.
Merge topic 'ninja-compile-link-pool' into next

8a9587a 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

8e393fb Ninja: job pool support for compiling and linking