Switch default JVM target to 1.8

#KT-29405 Fixed

compiler/testData/codegen/bytecodeText/boxingOptimization/hashCodeOnNonNull.kt

@@ -0,0 +1,11 @@
+// IGNORE_BACKEND: JVM_IR
+// IGNORE_BACKEND_FIR: JVM_IR
+
+fun foo() {
+    val x: Int? = 6
+    val hc = x!!.hashCode()
+}
+
+// 1 java/lang/Integer.hashCode \(I\)I
+// 0 java/lang/Integer.valueOf
+// 0 intValue

compiler/testData/codegen/bytecodeText/boxingOptimization/kt7224.kt

@@ -4,4 +4,4 @@ fun box(): String {
     return "OK"
 }
 
-// 1 INVOKESTATIC java/lang/Integer.valueOf
+// 0 INVOKESTATIC java/lang/Integer.valueOf

compiler/testData/codegen/bytecodeText/boxingOptimization/unsafeRemoving.kt

@@ -15,9 +15,6 @@ fun foo() {
     val b = arrayOfNulls<Int>(4)
     b[100] = 5
 
-    val x: Int? = 6
-    val hc = x!!.hashCode()
-
     val y: Int? = 7
     val z: Int? = 8
     val res = y === z
@@ -26,5 +23,5 @@ fun foo() {
     val c2: Any = if (1 != one) 0 else "abc"
 }
 
-// 9 java/lang/Integer.valueOf
+// 8 java/lang/Integer.valueOf
 // 0 intValue

compiler/testData/codegen/bytecodeText/hashCode/hashCode_1_6.kt

@@ -1,3 +1,5 @@
+// JVM_TARGET: 1.6
+
 fun box(): String {
     true.hashCode()
     1.toByte().hashCode()

compiler/testData/codegen/bytecodeText/inlineClasses/skipCallToUnderlyingValueOfInlineClass.kt

@@ -9,7 +9,7 @@ inline class UInt(val value: Int)
 fun test(u1: UInt, u2: UInt) {
     val a = u1.value
 
-    val b = u1.value.hashCode() // box int to call hashCode
+    val b = u1.value.hashCode()
     val c = u1.value + u2.value
 }
 
@@ -18,5 +18,5 @@ fun test(u1: UInt, u2: UInt) {
 // 0 INVOKESTATIC UInt\$Erased.box
 // 0 INVOKEVIRTUAL UInt.unbox
 
-// 1 valueOf
-// 0 intValue
+// 0 valueOf
+// 0 intValue

compiler/testData/codegen/bytecodeText/unsignedTypes/unsignedIntCompare_before.kt

@@ -1,4 +1,5 @@
 // WITH_RUNTIME
+// JVM_TARGET: 1.6
 
 val ua = 1234U
 val ub = 5678U