Add debug assertions to compiler profile

Working on the compiler without debug assertions is not a very
productive way to work on the compiler.

Author: Noratrieb

src/bootstrap/defaults/config.compiler.toml

@@ -8,6 +8,8 @@ compiler-docs = true
 # where adding `debug!()` appears to do nothing.
 # However, it makes running the compiler slightly slower.
 debug-logging = true
+# Enables debug assertions, which guard from many mistakes when working on the compiler.
+debug-assertions = true
 # Get actually-useful information from backtraces, profiling, etc. with minimal added bytes
 debuginfo-level = "line-tables-only"
 # This greatly increases the speed of rebuilds, especially when there are only minor changes. However, it makes the initial build slightly slower.