fix(tstest): preserve streaming console output and correctly buffer incomplete TAP lines

ts/tstest.classes.tap.testresult.ts

@@ -10,7 +10,7 @@ export class TapTestResult {
   constructor(public id: number) {}
 
   /**
-   * adds a logLine to the log buffer of the test
+   * adds a logLine to the log buffer of the test (with newline appended)
    * @param logLine
    */
   addLogLine(logLine: string) {
@@ -19,6 +19,15 @@ export class TapTestResult {
     this.testLogBuffer = Buffer.concat([this.testLogBuffer, logLineBuffer]);
   }
 
+  /**
+   * adds raw text to the log buffer without appending newline (for streaming output)
+   * @param text
+   */
+  addLogLineRaw(text: string) {
+    const logLineBuffer = Buffer.from(text);
+    this.testLogBuffer = Buffer.concat([this.testLogBuffer, logLineBuffer]);
+  }
+
   setTestResult(testOkArg: boolean) {
     this.testOk = testOkArg;
     this.testSettled = true;