Interop, backend: add bitsTo{Float,Double} intrinsics

Interop/Runtime/src/jvm/kotlin/kotlinx/cinterop/JvmUtils.kt

@@ -1,4 +1,7 @@
 package kotlinx.cinterop
 
 internal fun decodeFromUtf8(bytes: ByteArray) = String(bytes)
-internal fun encodeToUtf8(str: String) = str.toByteArray()
+internal fun encodeToUtf8(str: String) = str.toByteArray()
+
+fun bitsToFloat(bits: Int): Float = java.lang.Float.intBitsToFloat(bits)
+fun bitsToDouble(bits: Long): Double = java.lang.Double.longBitsToDouble(bits)

Interop/Runtime/src/native/kotlin/kotlinx/cinterop/NativeUtils.kt

@@ -1,5 +1,7 @@
 package kotlinx.cinterop
 
+import konan.internal.Intrinsic
+
 internal fun decodeFromUtf8(bytes: ByteArray): String = kotlin.text.fromUtf8Array(bytes, 0, bytes.size)
 
 fun encodeToUtf8(str: String): ByteArray {
@@ -13,4 +15,10 @@ fun encodeToUtf8(str: String): ByteArray {
         result[index] = char.toByte()
     }
     return result
-}
+}
+
+@Intrinsic
+external fun bitsToFloat(bits: Int): Float
+
+@Intrinsic
+external fun bitsToDouble(bits: Long): Double