test: switch repl import-no-crash to in-process REPL

Replace the child_process.spawn-based regression test with the
in-process startNewREPLServer pattern (similar to test-repl-null.js).
This is faster, avoids subprocess flake, and lets the test assert on
the REPL output stream directly instead of bytes piped through stdio.

Verified to still catch the regression: the test exits with code 1
against unpatched v26.1.0 (acorn SyntaxError escapes) and exits 0
against the fix.

Signed-off-by: Abdelhadi Sabani <asabani.work@gmail.com>

Author: awbx

test/parallel/test-repl-import-statement-no-crash.js

@@ -0,0 +1,31 @@
+'use strict';
+// Regression test for https://github.com/nodejs/node/issues/63551:
+// Typing a bare `import` keyword in the REPL used to terminate the process.
+//
+// V8 throws SyntaxError("Cannot use import statement outside a module"),
+// which the REPL enriched with a dynamic-import suggestion via
+// `toDynamicImport`. That helper called acorn without a try/catch; on
+// incomplete input acorn threw, and the exception escaped the REPL's input
+// pipeline to crash the process.
+//
+// The fix wraps the acorn call in try/catch and falls back to a plain
+// error message when the line cannot be parsed as a complete import
+// statement. This test asserts that:
+//   1. Emitting an incomplete `import` line through the REPL does not
+//      throw out of the line-handler, and
+//   2. The REPL still surfaces a SyntaxError to the user.
+
+require('../common');
+const assert = require('assert');
+const { startNewREPLServer } = require('../common/repl');
+
+const { replServer, output } = startNewREPLServer();
+
+replServer.emit('line', 'import');
+replServer.emit('line', '.exit');
+
+assert.match(output.accumulator, /SyntaxError/);
+assert.match(
+  output.accumulator,
+  /Cannot use import statement inside the Node\.js REPL\b/,
+);