Remove c++ macros that are moving to common packages (#1953)

* (probably) fix PXT_BUFFER_DATA, need to set up docker to test

* switch to adding new macros

* more macros and rename some

* get data length in bytes

* remove macros that were moved to common packages

* bump common packages to include reqd pr

libs/core/platform.h

@@ -1,13 +1,3 @@
 // helpful define to handle C++ differences in package
 #define PXT_MICROBIT_TAGGED_INT 1
-
-// cross version compatible way of access data field
-#ifndef PXT_BUFFER_DATA
-#define PXT_BUFFER_DATA(buffer) buffer->data
-#endif
-
-#ifndef PXT_CREATE_BUFFER
-#define PXT_CREATE_BUFFER(data, len) pxt::mkBuffer(data, len)
-#endif
-
 #define PXT_POWI 1

package.json

@@ -45,7 +45,7 @@
     "@types/web-bluetooth": "0.0.4"
   },
   "dependencies": {
-    "pxt-common-packages": "6.5.19",
+    "pxt-common-packages": "6.5.20",
     "pxt-core": "5.9.3"
   }
 }