Stub generation infrastructure (except for metadata generation) for KAPT+K2

This commit includes the basic Java stubs generation infrastructure and
the corresponding tests. The main entry point is called
Kapt4StubGenerator. Calls to it from production code will be added in a
separate commit.

 #KT-51982

plugins/kapt3/kapt3-compiler/testData/converter/invalidFieldName.kt

@@ -1,3 +1,4 @@
+// FIR_BLOCKED: LC don't support illegal java identifiers
 enum class Color {
     BLACK, `WHI-TE`
 }
@@ -5,5 +6,5 @@ enum class Color {
 @Anno(Color.`WHI-TE`)
 annotation class Anno(val color: Color)
 
-// EXPECTED_ERROR: (kotlin:5:1) an enum annotation value must be an enum constant
+// EXPECTED_ERROR: (kotlin:6:1) an enum annotation value must be an enum constant
 // EXPECTED_ERROR: (other:-1:-1) 'WHI-TE' is an invalid Java enum value name