Revert [JS IR] commits that failed build

Revert "[JS IR] Build hybrid versions of stdlib and kotlin.test"
This reverts commit b9f88350dd.

Revert "[JS IR] Add gradle plugin integration tests"
This reverts commit d872b27663.

Revert "Update bootstrap"
This reverts commit bc47594c7a.

Revert "[JS IR] Support generating both IR and pre-IR libraries"
This reverts commit 1b8df45bfe.

compiler/incremental-compilation-impl/test/org/jetbrains/kotlin/incremental/AbstractIncrementalJsKlibCompilerRunnerTest.kt

@@ -10,8 +10,10 @@ abstract class AbstractIncrementalJsKlibCompilerRunnerTest : AbstractIncremental
             libraries = "build/js-ir-runtime/full-runtime.klib"
             outputFile = File(destinationDir, "${testDir.name}.klib").path
             sourceMap = true
+            irBackend = true
+            irProduceOnly = "klib"
             // Don't zip klib content since date on files affect the md5 checksum we compute to check whether output files identical
-            irProduceKlibDir = true
+            irLegacyGradlePluginCompatibility = true
         }
 
     override val buildLogFinder: BuildLogFinder