Do not treat directory with copied test sources for js library as source root, as it confuses debugger under certain circumstances.

Remove duplicated test.

libraries/stdlib/test/text/StringUtilTest.kt

@@ -1,13 +0,0 @@
-package test.text
-
-import kotlin.*
-import kotlin.test.*
-import org.junit.Test as test
-
-class StringUtilTest() {
-    @test fun toPattern() {
-        val re = """foo""".toPattern()
-        val list = re.split("hellofoobar").toList()
-        assertEquals(listOf("hello", "bar"), list)
-    }
-}