lexer: Remove match-at dependency, use RegExp (#1447)

* lexer: Remove `match-at` dependency, use RegExp

* chore(package): update flow-bin to version 0.75.0

* Fix flow error

* Remove unused flow libs

* Minor fix

* Throw an error when `RegExp.exec` jumps

test/errors-spec.js

@@ -285,9 +285,9 @@ describe("Lexer:", function() {
 
     describe("#_innerLex", function() {
         it("rejects lone surrogate char", function() {
-            expect("\udcba").toFailWithParseError(
+            expect("\udcba ").toFailWithParseError(
                    "Unexpected character: '\udcba' at position 1:" +
-                    " \udcba\u0332");
+                    " \udcba\u0332 ");
         });
         it("rejects lone backslash at end of input", function() {
             expect("\\").toFailWithParseError(