Adjust tests to use current x-file-type header name

Author: brandonpayton

packages/php-wasm/node/src/test/php-request-handler.spec.ts

@@ -149,7 +149,7 @@ describe.each(SupportedPHPVersions)(
 							type: 'response',
 							response: new PHPResponse(
 								404,
-								{ 'x-backfill-from': ['remote-host'] },
+								{ 'x-file-type': ['static'] },
 								new TextEncoder().encode('404 File not found')
 							),
 						};
@@ -163,7 +163,7 @@ describe.each(SupportedPHPVersions)(
 				expect(response).toEqual({
 					httpStatusCode: 404,
 					headers: {
-						'x-backfill-from': ['remote-host'],
+						'x-file-type': ['static'],
 					},
 					bytes: expect.any(Uint8Array),
 					errors: '',