Extract kotlin-reflect-api module out of kotlin-reflect

This is needed only for faster compilation of the Kotlin project itself
and has no effect on the public artifact
org.jetbrains.kotlin:kotlin-reflect.

The problem this is solving is the rebuild of the project once anything
has been changed in modules in 'core' (even inside function bodies, i.e.
a non-API change). Previously, changes in 'core' led to the compilation
of kotlin-reflect, which led to the rebuild of all modules depending on
kotlin-reflect directly or indirectly (which is almost all modules in
the project) because kotlin-reflect's artifacts are custom-built and the
changes can not be picked up incrementally. But 99.9% of the time the
initial changes in 'core' could not have any effect on the usages of
kotlin-reflect, because classes from those modules are moved to an
internal package in kotlin-reflect and thus are an internal
implementation detail.

Now, changes in 'core' still lead to the compilation of kotlin-reflect
and to the process of building the custom jar. But if a module depends
on kotlin-reflect-api, not kotlin-reflect, then the incremental
difference checker will detect that the module does not have to be
recompiled if there hasn't been any changes to the API of
kotlin-reflect-api. Which means that the module will not be rebuilt on
every change in 'core'.

This commit only introduces the new module. The dependencies
(kotlin-reflect -> kotlin-reflect-api) are replaced in the next commit.

generators/src/org/jetbrains/kotlin/generators/protobuf/GenerateProtoBuf.kt

@@ -69,9 +69,12 @@ fun main(args: Array<String>) {
 
         for (protoPath in PROTO_PATHS) {
             execProtoc(protoPath.file, protoPath.outPath)
+            renamePackages(protoPath.file, protoPath.outPath)
             modifyAndExecProtoc(protoPath)
         }
 
+        generateJvmPackageTableToBuildSrc()
+
         println()
         println("Do not forget to run GenerateProtoBufCompare")
     }
@@ -108,8 +111,6 @@ private fun execProtoc(protoPath: String, outPath: String) {
     if (processOutput.stderr.isNotEmpty()) {
         throw AssertionError(processOutput.stderr)
     }
-
-    renamePackages(protoPath, outPath)
 }
 
 private fun renamePackages(protoPath: String, outPath: String) {
@@ -143,7 +144,9 @@ private fun modifyAndExecProtoc(protoPath: ProtoPath) {
     debugProtoFile.writeText(modifyForDebug(protoPath))
     debugProtoFile.deleteOnExit()
 
-    execProtoc(debugProtoFile.path, "build-common/test")
+    val outPath = "build-common/test"
+    execProtoc(debugProtoFile.path, outPath)
+    renamePackages(debugProtoFile.path, outPath)
 }
 
 private fun modifyForDebug(protoPath: ProtoPath): String {
@@ -158,3 +161,7 @@ private fun modifyForDebug(protoPath: ProtoPath): String {
     }
     return text
 }
+
+private fun generateJvmPackageTableToBuildSrc() {
+    execProtoc("core/descriptors.jvm/src/jvm_package_table.proto", "buildSrc/src/main/java")
+}