This reverts commit 6807ed6642.
The reason is that Kotlin compilers until and including version 1.6.10
have code that detects obsolete coroutines via these version
requirements (see `versionAndReleaseCoroutinesMismatch`). Since Kotlin
1.6.10 can read metadata of version 1.7, the earliest we can drop these
version requirements is Kotlin 1.8.0.
Coroutines are a stable feature since 1.3. Version requirement on
suspend functions, or functions mentioning suspend function types in the
signature, was needed to prevent older compilers from reading metadata
that they can't properly use. It's not needed anymore because a newer
metadata version prevents older compilers from reading any metadata
altogether.
Also, computing isSuspendOrHasSuspendTypesInSignature took ~0.5% of
backend time on compilation of intellij (related to KT-48233).
Alexander Udalov