Fix JDK-dependent stdlib tests after advancing jvmTarget

libraries/stdlib/jvm/test/exceptions/ExceptionJVMTest.kt

@@ -6,7 +6,6 @@
 package test.exceptions
 
 import test.collections.assertArrayNotSameButEquals
-import test.testOnJvm7AndAbove
 import java.io.*
 import java.nio.charset.Charset
 import kotlin.test.*
@@ -96,9 +95,8 @@ class ExceptionJVMTest {
         e1.initCause(e2)
         assertSame(e1, e2.cause)
         assertSame(e2, e1.cause)
-        testOnJvm7AndAbove {
-            val trace = e2.stackTraceToString()
-            assertTrue("CIRCULAR REFERENCE" in trace, trace)
-        }
+
+        val trace = e2.stackTraceToString()
+        assertTrue("CIRCULAR REFERENCE" in trace, trace)
     }
 }

libraries/stdlib/jvm/test/testUtilsJVM.kt

@@ -12,25 +12,6 @@ public actual fun assertTypeEquals(expected: Any?, actual: Any?) {
     assertEquals(expected?.javaClass, actual?.javaClass)
 }
 
-private val isJava6 = System.getProperty("java.version").startsWith("1.6.")
-
-internal actual fun String.removeLeadingPlusOnJava6(): String =
-    if (isJava6) removePrefix("+") else this
-
-private val isJava7 = System.getProperty("java.version").startsWith("1.7.")
-
-private val isJava8AndAbove = !isJava6 && !isJava7
-
-internal actual inline fun testOnNonJvm6And7(f: () -> Unit) {
-    if (isJava8AndAbove) {
-        f()
-    }
-}
-internal inline fun testOnJvm7AndAbove(f: () -> Unit) {
-    if (!isJava6) {
-        f()
-    }
-}
 public actual fun testOnJvm(action: () -> Unit) = action()
 public actual fun testOnJs(action: () -> Unit) {}
 
@@ -39,10 +20,8 @@ public fun <T> platformNull() = Collections.singletonList(null as T).first()
 
 public actual val isFloat32RangeEnforced: Boolean = true
 
-public actual val supportsSuppressedExceptions: Boolean get() = !isJava6
-
-// Named capturing groups are supported starting from java 7. However, retrieving them by name is not supported in java 7.
-public actual val supportsNamedCapturingGroup: Boolean get() = isJava8AndAbove
+public actual val supportsNamedCapturingGroup: Boolean
+    get() = System.getProperty("supportsNamedCapturingGroup")?.toBooleanStrict() ?: true
 
 public actual val supportsOctalLiteralInRegex: Boolean get() = true