FIR Completion: Add simple classifiers completion

- This also fixes a few test

idea/idea-completion/testData/basic/common/lambdaSignature/ParameterType1.kt

@@ -1,3 +1,4 @@
+// FIR_COMPARISON
 fun bar() {
     val handler = { i: <caret> }
 }

idea/idea-completion/testData/basic/common/lambdaSignature/ParameterType2.kt

@@ -1,3 +1,4 @@
+// FIR_COMPARISON
 fun bar() {
     val handler = { i: Int, s: <caret> }
 }

idea/idea-completion/testData/basic/common/lambdaSignature/ParameterType3.kt

@@ -1,3 +1,4 @@
+// FIR_COMPARISON
 fun bar() {
     val handler = { i: List<<caret>> }
 }

idea/idea-completion/testData/basic/common/lambdaSignature/ParameterType4.kt

@@ -1,3 +1,4 @@
+// FIR_COMPARISON
 fun bar() {
     val handler = { i: Map<String, <caret> }
 }

idea/idea-completion/testData/basic/common/lambdaSignature/ParameterType5.kt

@@ -1,3 +1,4 @@
+// FIR_COMPARISON
 fun bar() {
     val handler = { i: Int, list: List<String>, s: <caret> }
 }