Ruby: Move all integration tests.

We no longer need the platform-specific directories, so simplify the test organization.
If you don't want this change, just skip merging this PR. It's purely optional.

ruby/ql/integration-tests/diagnostics/syntax-error/bad.rb

@@ -0,0 +1,3 @@
+4 %%% 5
+
+if 1; 2

ruby/ql/integration-tests/diagnostics/syntax-error/diagnostics.expected

@@ -0,0 +1,46 @@
+{
+  "helpLinks": [
+    "https://docs.github.com/en/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/customizing-code-scanning"
+  ],
+  "location": {
+    "endColumn": 5,
+    "endLine": 1,
+    "file": "<test-root-directory>/bad.rb",
+    "startColumn": 4,
+    "startLine": 1
+  },
+  "markdownMessage": "A parse error occurred. Check the syntax of the file. If the file is invalid, correct the error or [exclude](https://docs.github.com/en/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/customizing-code-scanning) the file from analysis.",
+  "plaintextMessage": "A parse error occurred. Check the syntax of the file. If the file is invalid, correct the error or exclude the file from analysis.",
+  "severity": "warning",
+  "source": {
+    "extractorName": "ruby",
+    "id": "ruby/parse-error",
+    "name": "Could not process some files due to syntax errors"
+  },
+  "visibility": {
+    "statusPage": true
+  }
+}
+{
+  "helpLinks": [
+    "https://docs.github.com/en/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/customizing-code-scanning"
+  ],
+  "location": {
+    "endColumn": 7,
+    "endLine": 3,
+    "file": "<test-root-directory>/bad.rb",
+    "startColumn": 8,
+    "startLine": 3
+  },
+  "markdownMessage": "A parse error occurred (expected `end` symbol). Check the syntax of the file. If the file is invalid, correct the error or [exclude](https://docs.github.com/en/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/customizing-code-scanning) the file from analysis.",
+  "plaintextMessage": "A parse error occurred (expected end symbol). Check the syntax of the file. If the file is invalid, correct the error or exclude the file from analysis.",
+  "severity": "warning",
+  "source": {
+    "extractorName": "ruby",
+    "id": "ruby/parse-error",
+    "name": "Could not process some files due to syntax errors"
+  },
+  "visibility": {
+    "statusPage": true
+  }
+}

ruby/ql/integration-tests/diagnostics/syntax-error/test.py

@@ -0,0 +1,2 @@
+def test(codeql, ruby):
+    codeql.database.create()