Small performance gain by unwinding the string literal delimiter search

loop in the JSON parser by one more level.

FossilOrigin-Name: 4c587feac153e8ebe526559ec3d254f545f81e8d1ed3126f91a5ff25ec4aa72e

manifest

@@ -1,5 +1,5 @@
-C Clean\sup\sthe\sJSONB\sperformance\stest\sscript.
-D 2023-12-05T12:20:58.241
+C Small\sperformance\sgain\sby\sunwinding\sthe\sstring\sliteral\sdelimiter\ssearch\nloop\sin\sthe\sJSON\sparser\sby\sone\smore\slevel.
+D 2023-12-05T12:22:05.245
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -688,7 +688,7 @@ F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
 F src/hwtime.h f9c2dfb84dce7acf95ce6d289e46f5f9d3d1afd328e53da8f8e9008e3b3caae6
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
 F src/insert.c 3f0a94082d978bbdd33c38fefea15346c6c6bffb70bc645a71dc0f1f87dd3276
-F src/json.c 3635645a2a07070a38dade2ba34daa3f3633fd134a800cb05db236d68bc1b5c3
+F src/json.c 53d9e4ea2e1b33ea0f0dc629d08605748056333c57ff03ea8b6cfdcc585a4dc0
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 7432c944ff197046d67a1207790a1b13eec4548c85a9457eb0896bb3641dfb36
 F src/main.c 1b89f3de98d1b59fec5bac1d66d6ece21f703821b8eaa0d53d9604c35309f6f9
@@ -2145,8 +2145,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P a249ca657e624028bc6b3d2c2bcedd7162d118addb7d62ce519920cecebf1860
-R 458c3105955a68681dcfc6965be984aa
+P 905301075a7fc1010ee7e754867b1b698c9b8576d50e98125def32a5dfb7ee9d
+R ec589ba3fd8295a6ff09aeae12dc3bd7
 U drh
-Z 523674accd38155d2ed6d77fe8db57c8
+Z 7a001bd7445e746508caf3ed9f69266e
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-905301075a7fc1010ee7e754867b1b698c9b8576d50e98125def32a5dfb7ee9d
+4c587feac153e8ebe526559ec3d254f545f81e8d1ed3126f91a5ff25ec4aa72e

src/json.c

@@ -1412,11 +1412,13 @@ json_parse_restart:
     j = i+1;
     while( 1 /*exit-by-break*/ ){
       if( jsonIsOk[(u8)z[j]] ){
-        if( jsonIsOk[(u8)z[j+1]] ){
-          j += 2;
-          continue;
-        }else{
+        if( !jsonIsOk[(u8)z[j+1]] ){
           j += 1;
+        }else if( !jsonIsOk[(u8)z[j+2]] ){
+          j += 2;
+        }else{
+          j += 3;
+          continue;
         }
       }
       c = z[j];