api/router: avoid unneeded loops and fix path match (#1594)

* api/router: avoid unneeded loops and fix path match

* if match found in google api path syntax, not try pcre loop
* if path is not ending via $ sign, append it to pcre to avoid matching other strings like
  /api/account/register can be matched to /api/account
* api: add tests and validations

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

proto/test.proto

@@ -6,7 +6,12 @@ service Test {
 	rpc Call(Request) returns (Response) {
     option (google.api.http) = { post: "/api/v0/test/call/{uuid}"; body:"*"; };
 	};
-
+	rpc CallPcre(Request) returns (Response) {
+    option (google.api.http) = { post: "^/api/v0/test/call/pcre/?$"; body:"*"; };
+	};
+	rpc CallPcreInvalid(Request) returns (Response) {
+    option (google.api.http) = { post: "^/api/v0/test/call/pcre/invalid/?"; body:"*"; };
+	};
 }
 
 message Request {