v.gen.js: fix method calls and other codegen parts, rand module compiles (#11205)

vlib/builtin/js/builtin.js.v

@@ -4,3 +4,35 @@ module builtin
 pub fn js_throw(s any) {
 	#throw (s instanceof Error ? s : new Error(s))
 }
+
+pub fn println(s any) {
+	$if js_freestanding {
+		#print(s.toString())
+	} $else {
+		#console.log(s.toString())
+	}
+}
+
+pub fn print(s any) {
+	$if js_node {
+		#$process.stdout.write(s.toString())
+	} $else {
+		panic('Cannot `print` in a browser, use `println` instead')
+	}
+}
+
+pub fn eprintln(s any) {
+	$if js_freestanding {
+		#print(s.toString())
+	} $else {
+		#console.error(s.toString())
+	}
+}
+
+pub fn eprint(s any) {
+	$if js_node {
+		#$process.stderr.write(s.toString())
+	} $else {
+		panic('Cannot `eprint` in a browser, use `println` instead')
+	}
+}