Change ScriptSplitter to use charAt instead of toString endsWith

Fixed an issue with the `ScriptSplitter#split` method, where encountering whitespace would result in the StringBuilder building the entire string just to check the last character in the string.

Author: hspragg-godaddy

modules/database-commons/src/main/java/org/testcontainers/ext/ScriptSplitter.java

@@ -36,7 +36,7 @@ void split() {
                     //skip
                     break;
                 case WHITESPACE:
-                    if (!sb.toString().endsWith(" ")) {
+                    if (sb.length() != 0 && sb.charAt(sb.length() - 1) != ' ') {
                         sb.append(' ');
                     }
                     break;