2/2 analysis-api: Initial implementation for contracts

Review: https://jetbrains.team/p/kt/reviews/7652

Put this change into a separate commit because:
1. The change is boring and clutters the diff of the first commit
2. The first commits is already too big

analysis/analysis-api/testData/symbols/symbolByPsi/enumEntryOverride.descriptors.txt

@@ -2,6 +2,7 @@ KtFunctionSymbol:
   annotationsList: []
   callableIdIfNonLocal: null
   contextReceivers: []
+  contractEffects: []
   hasStableParameterNames: true
   isBuiltinFunctionInvoke: false
   isExtension: false
@@ -29,6 +30,7 @@ KtFunctionSymbol:
   annotationsList: []
   callableIdIfNonLocal: null
   contextReceivers: []
+  contractEffects: []
   hasStableParameterNames: true
   isBuiltinFunctionInvoke: false
   isExtension: false
@@ -71,6 +73,7 @@ KtFunctionSymbol:
   annotationsList: []
   callableIdIfNonLocal: null
   contextReceivers: []
+  contractEffects: []
   hasStableParameterNames: true
   isBuiltinFunctionInvoke: false
   isExtension: false
@@ -167,6 +170,7 @@ KtFunctionSymbol:
   annotationsList: []
   callableIdIfNonLocal: null
   contextReceivers: []
+  contractEffects: []
   hasStableParameterNames: true
   isBuiltinFunctionInvoke: false
   isExtension: false
@@ -194,6 +198,7 @@ KtFunctionSymbol:
   annotationsList: []
   callableIdIfNonLocal: null
   contextReceivers: []
+  contractEffects: []
   hasStableParameterNames: true
   isBuiltinFunctionInvoke: false
   isExtension: false
@@ -256,6 +261,7 @@ KtFunctionSymbol:
   annotationsList: []
   callableIdIfNonLocal: /MyEnumClass.foo
   contextReceivers: []
+  contractEffects: []
   hasStableParameterNames: true
   isBuiltinFunctionInvoke: false
   isExtension: false
@@ -283,6 +289,7 @@ KtFunctionSymbol:
   annotationsList: []
   callableIdIfNonLocal: /MyEnumClass.foo
   contextReceivers: []
+  contractEffects: []
   hasStableParameterNames: true
   isBuiltinFunctionInvoke: false
   isExtension: false