Remove soft keyword coroutine & isCoroutine from ValueParameterDescriptor.

compiler/testData/psi/SoftKeywords.kt

@@ -17,7 +17,6 @@ internal
 in
 out
 suspend
-coroutine
  class Bar<abstract, abstract enum : T, out open,
     public protected private internal abstract
     open

compiler/testData/psi/SoftKeywords.txt

@@ -57,8 +57,6 @@ JetFile: SoftKeywords.kt
       PsiElement(out)('out')
       PsiWhiteSpace('\n')
       PsiElement(suspend)('suspend')
-      PsiWhiteSpace('\n')
-      PsiElement(coroutine)('coroutine')
     PsiWhiteSpace('\n ')
     PsiElement(class)('class')
     PsiWhiteSpace(' ')