Add operator 'rem' as extension to BigInteger

#KT-14650 Fixed

 Note that after this change behaviour of '%' on BigInteger is changed,
now it works like a proper remainder

compiler/testData/codegen/box/operatorConventions/percentAsModOnBigIntegerWithoutRem.kt

@@ -0,0 +1,11 @@
+// TARGET_BACKEND: JVM
+
+// LANGUAGE_VERSION: 1.0
+// FULL_JDK
+
+import java.math.BigInteger
+
+fun box(): String {
+    val m = BigInteger.valueOf(-2) % BigInteger.valueOf(3)
+    return if (m != BigInteger.valueOf(1)) "Fail: BigInteger(-2) mod BigInteger(3) == $m" else "OK"
+}

compiler/testData/codegen/light-analysis/operatorConventions/percentAsModOnBigIntegerWithoutRem.txt

@@ -0,0 +1,3 @@
+public final class PercentAsModOnBigIntegerWithoutRemKt {
+    public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
+}